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Results for “Collagen Type I, alpha 1 Chain”

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PubMed1982

"Embryonic" collagen (type I trimer) alpha 1-chains are genetically distinct from type I collagens alpha 1-chains.

Our laboratory has previously demonstrated that cell lines derived from early embryonic mouse sources produce procollagen and collagen and suggested that this material represents a new genetic type of collagen. Evidence was presented using carboxymethyl cellulose chromatography, analytical isoelectric focusing, cyanogen bromide peptide analysis, amino acid analysis, and carbohydrate analysis which demonstrated that this "embryonic" collagen consisted of three identical alpha-chains, distinctly different from types I, II and III and IV collagen and thus probably represented a new type of collagen. Further evidence is presented using Staphylococcus aureus V-8 protease generated peptide maps and immunological studies using antisera prepared against "embryonic" collagen and procollagen. These data clearly demonstrated that "embryonic" collagen is clearly distinct from type I alpha-chains and represents a unique genetic species of collagen.

Animals↗

PubMed1998

Expression of type XVII collagen alpha 1 chain mRNA in the mouse heart.

The type XVII collagen alpha 1 chain has been identified as a component of the type I hemidesmosome, and is thus thought to play a role in extracellular matrix (ECM) maintenance and signal transduction between the cell and the ECM. We examined the expression of type XVII collagen alpha 1 chain mRNA in the mouse heart by Northern blot analysis and determined the sequential changes of its expression in different developmental stages of the heart using the reverse transcriptase-polymerase chain reaction (RT-PCR) method. Northern blotting: Total RNA was extracted from 10 adult mouse hearts by the guanidine/cesium method. Hybridization was performed with mouse cDNA for alpha 1 (XVII) collagen. RT-PCR: Total RNA was extracted from 7 embryos, 4 neonates and 8 adult mice. Reverse transcription was performed using oligo-dT primer and MMLV. Amplification was carried out in alpha 1 (XVII) collagen and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). GAPDH served as an internal control. Northern blotting revealed a 5.6 kb signal that was identical to that of the alpha 1 (XVII) of skin and transformed keratinocyte reported previously. The sequences of the PCR products were also identical to those reported. The normalized expression ratios of alpha 1 (XVII) were 0.91 +/- 0.20 in the embryonic heart, 0.36 +/- 0.20 in the neonatal heart and 0.96 +/- 0.21 in the adult heart. In conclusion, we identified the expression of type XVII collagen alpha 1 chain mRNA in the mouse heart, suggesting that the type I hemidesmosome is located in the heart. The results of the RT-PCR at different developmental stages of the heart suggest that type XVII collagen contributes not only to cardiogenesis in the embryonic stage but also to maintenance of architecture and function in the adult heart.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1991

Immunity to type XI collagen in mice. Evidence that the alpha 3(XI) chain of type XI collagen and the alpha 1(II) chain of type II collagen share arthritogenic determinants and induce arthritis in DBA/1 mice.

To determine whether native bovine type XI collagen (BXI) is arthritogenic, five strains of inbred mice were immunized with BXI/CFA. Arthritis was not observed in any of these strains, though it was prevalent in DBA/1 and B10.RIII controls immunized with bovine type II collagen (BII). Antisera from BXI-immunized mice reacted with mouse type XI collagen (MsXI), weakly with the alpha-chains of BXI, and minimally with mouse type II collagen (MsII). However, antisera to BII reacted with MsII and MsXI, indicating antibodies to conformation-independent epitopes shared by alpha 1(II) and alpha 3(XI). Mice immunized with BXI containing a small amount of BII developed arthritis much like those immunized with BII; sera from these mice reacted with MsXI and MsII. Delayed-type hypersensitivity responses differed from IgG responses, i.e., BXI elicited responses to alpha 1(XI), alpha 2(XI), alpha 3(XI), and alpha 1(II); BII, to alpha 3(XI) and alpha 1(II) exclusively. To determine whether alpha 1(XI), alpha 2(XI), alpha 3(XI), and alpha 1(II) are arthritogenic, DBA/1J mice were immunized with each alpha-chain. Arthritis was seen in mice injected with alpha 3(XI) or alpha 1(II). Sera to both alpha-chains reacted similarly with MsII and peptide fragment alpha 1(II)-CB11. Epitope mapping using polyclonal and mAb to type II collagen revealed that all polyclonal and 11 of 14 mAb reacted with alpha 3(XI) and alpha 1(II), whereas three mAb reacted only with alpha 1(II). In conclusion, BXI is immunogenic but not arthritogenic in five strains of mice, whereas alpha 3(XI) and alpha 1(II) are arthritogenic and immunogenic in DBA/1 mice and share greater than or equal to 11 epitopes recognized by autoantibody.

Animals↗

PubMed1989

Assignment of the gene coding for the alpha 1 chain of collagen type XIII (COL13A1) to human chromosome region 10q11----qter.

The gene coding for the alpha 1 chain of human type XIII collagen. COL13A1, is assigned to chromosome region 10q11----qter by Southern blot hybridization of DNA from 24 human x rodent somatic cell hybrids using a cloned cDNA as probe. A number of previous reports indicate that 10 of the collagen genes are located on six autosomes, but no other collagen genes have been found on chromosome 10. The data therefore provide further evidence for the dispersion of members of the collagen gene family throughout the genome.

Animals↗

PubMed1997

Decreased beta-isomerization of the C-terminal telopeptide of type I collagen alpha 1 chain in Paget's disease of bone.

In Paget's disease of bone, the normal lamellar bone is replaced by a woven structure with an irregular arrangement of collagen fibers. In this study, we investigated whether the degree of beta-isomerization within C-telopeptide of alpha 1 chain of type I collagen was altered in Paget's disease compared with other bone diseases with no alteration of bone structure. In Paget's disease (n = 26), but not in patients with primary hyperparathyroidism (n = 6) or hyperthyroidism (n = 17), the urinary excretion of nonisomerized (alpha) fragments derived from degradation of type I collagen C-telopeptide (CTX) was markedly increased compared with beta-isomerized CTX (+ 13-fold vs. + 3.5-fold over controls) resulting in an urinary alpha CTX/beta CTX ratio 3-fold higher than in controls (2.6 +/- 1.0 vs. 0.8 +/- 0.3, p < 0.001). In five pagetic patients in complete remission, as demonstrated by normal total alkaline phosphatase activity, the alpha CTX/beta CTX ratio was normal. The immunohistochemistry of normal and pagetic human bone sections showed a preferential distribution of alpha CTX within woven structure, while lamellar bone was intensely stained with an anti-beta CTX antibody, suggesting a lower degree of beta-isomerization of type I collagen in the woven pagetic bone. In collagenase digest of human bone specimens, we found a lower proportion of beta-isomerized type I collagen molecules in pagetic bone (40% of beta CTX) than in normal bone taken from trabecular (68%) and cortical compartments (71%). In conclusion, we found that in Paget's disease the alpha CTX/beta CTX ratio in bone and in urine is markedly increased. This altered beta isomerization can be accurately detected in vivo by measuring urinary degradation products arising from bone resorption.

Adult↗

PubMed2000

Serum CrossLaps for monitoring the response in individuals undergoing antiresorptive therapy.

The Serum CrossLaps (CTx) enzyme-linked immunosorbent assay (ELISA) is specific for a cross-linked, beta-aspartate-isomerized form of the epitope EKAHDGGR derived from the carboxyterminal telopeptide region of type I collagen alpha(1) chain. Collagen type I fragments reactive in the CTx assay are released during osteoclastic bone resorption and can be used as a measure of bone resorption activity. Our objectives were to assess the intraindividual variation of serum CTx concentration as well as the clinical value of the serum CTx assay for monitoring antiresorptive therapy in individual patients. The influence of the sampling time and fasting on the serum CTx measurements was studied with the aim of determining an optimal sampling protocol. Studies of circadian variation in serum CTx concentration in 15 postmenopausal women showed that fasting significantly reduced the average circadian variation of the marker from 36% to 8.7%. This was further supported by assessing short-term (2 weeks) intraindividual variation in ten postmenopausal women who were sampled in the morning, either fasting or nonfasting. The average short-term intraindividual coefficient of variation (CV) was 7.9% in the samples obtained from fasting women, and 14.3% in the samples obtained from nonfasting women. The long-term intraindividual biological variation was 13.4% in 44 postmenopausal women sampled every 6 months (fasting morning samples) over a 1 year period. The ability of the serum CTx assay to monitor individual responses to antiresorptive therapy was assessed in studies of the effects of hormone replacement therapy (HRT) and bisphosphonate (alendronate). Serum samples (morning fasting) were obtained from postmenopausal women treated with either bisphosphonate or HRT at baseline and then after various timepoints of therapy. Spine bone mineral density (BMD) measurements were carried out and the annual percentage change in spine BMD (alphaBMD) was calculated. Sixteen of 17 (94%) of the HRT-treated and 12 of 13 (92%) of the bisphosphonate-treated women showed a decrease in serum CTx after 6 months that was greater than the calculated least significant change (LSC) of the marker (LSC(CTx)). In contrast, only 59% of the HRT-treated and 64% of the bisphosphonate-treated women showed a response in spine BMD greater than the LSC(BMD) 0%) from women with a loss in spine BMD (alphaBMD < 0%). In conclusion, the serum CTx showed high specificity and sensitivity for monitoring individual responses to antiresorptive therapy. More than 92% of the treated women showed significant responses in serum CTx measurements after 6 months.

Absorptiometry, Photon↗

PubMed1994

Immunohistochemical study of alpha 1-5 chains of type IV collagen in hereditary nephritis.

The distribution of alpha 1-5 chains of type IV collagen [alpha 1-5(IV)] in the glomerular basement membrane (GBM) and epidermal basement membrane (EBM) of 23 families with hereditary nephritis was examined by indirect immunofluorescence. These families were divided into three clinicopathological groups. Group I (10 families) patients showed a widespread "basket weave" pattern of the GBM and a family history of nephritis was present. Group II (6 families) patients showed a widespread "basket weave" change without a family history of nephritis. Group III (7 families) patients showed a widespread attenuation of the GBM but no "basket weave" change, and had a family history of nephritis and chronic renal failure. alpha 1(IV) and alpha 2(IV) were present in all affected and unaffected family members and controls. All normal family members and controls expressed alpha 3(IV), alpha 4(IV) and alpha 5(IV) in the GBM and alpha 5(IV) in the EBM in a diffuse pattern. All group I families and three of the group II families exhibited complete loss of the alpha 5(IV) antigen from the GBM and EBM in male patients, and segmental loss of the alpha 5(IV) antigen in female patients. In these families the alpha 3(IV) and alpha 4(IV) antigens were completely lost from the GBM in male patients with severe nephritis, whereas alpha 3(IV) alpha 4(IV) were present but diminished in male patients with mild nephritis. Three group II and all group III families expressed the alpha 3-5(IV) antigens in an identical manner to that of normal controls. These findings indicate that the heterogeneity of hereditary nephritis reflects a variety of aberrant expression patterns of alpha 3-5(IV) and that immunohistochemical examination of alpha 5(IV) in the EBM is a useful method for the diagnosis of X-linked Alport syndrome.

Adult↗

PubMed1993

An RT-PCR-SSCP screening strategy for detection of mutations in the gene encoding the alpha 1 chain of type I collagen: application to four patients with osteogenesis imperfecta.

A strategy has been developed to allow the screening for mutations in the cDNA of the type I collagen alpha 1 chain. The method involves polymerase chain reaction amplification of four overlapping segments covering the majority of the sequence coding for alpha 1(I) collagen. Four or five restriction endonuclease digestions are performed for each segment and digested samples subjected to single strand conformation polymorphism analysis. Mutations are finally defined by DNA sequence analysis. The application to the detection of mutations in four patients with lethal and non-lethal forms of osteogenesis imperfecta is described. In each of these patients, the heterozygous mutation identified resulted in substitution of different glycine residues with serines. In addition to these deleterious mutations, several novel silent variants were characterised. The strategy provides a rapid approach to screening for mutations and polymorphisms in alpha 1(I) collagen cDNA and is of general interest in scanning large regions of DNA for sequence changes.

Adult↗

PubMed1991

Altered steady-state levels of mRNA coding for extracellular matrices in renal tissues of ddY mice, an animal model for IgA nephropathy.

Correlations between the steady-state mRNA levels of extracellular matrices using specific cDNA probes for the alpha 1 chain of type IV collagen (alpha 1 (IV) chain); laminin A, B1, and B2 chains; and heparan sulfate proteoglycan (HSPG); and glomerular injuries in ddY mice were evaluated. Eight-, sixteen- and forty-week-old ddY mice were used in this study. ICR mice of the same age served as control. Extracted total RNA of pooled kidneys was fixed on a filter and then hybridized with the cDNA probes. Renal cryostat sections were incubated with rabbit anti-mouse type IV collagen, laminin, and HSPG antisera and then stained with FITC-labeled goat anti-rabbit IgG antiserum. The sections were also stained with FITC-labeled goat anti-mouse IgA, IgM, IgG, and C3 antisera. In light microscopy, the average number of glomerular cells was calculated at each age. Increased expression of extracellular matrices genes for the alpha 1(IV) chain; laminin A, B1, and B2 chains; and HSPG was found in renal tissues of ddY mice. Staining of type IV collagen, laminin, and HSPG was observed in renal tissues of ddY mice at each age. Increased proteinuria in 40-week-old ddY mice might be related to the decrease in glomerular basement membrane HSPG which acts as the anionic sites in such areas. Marked proliferation and or expansion of glomerular cells and mesangial matrices were observed in 40 week-old-ddY mice. The intensity of IgA and C3 deposits in the glomeruli was parallel to the levels of mRNA for such components.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Expression of mRNAs coding for the alpha 1 chain of type XIII collagen in human fetal tissues: comparison with expression of mRNAs for collagen types I, II, and III.

This paper describes the topographic distribution of the multiple mRNAs coding for a novel human short-chain collagen, the alpha 1 chain of type XIII collagen. To identify the tissues and cells expressing these mRNAs, human fetal tissues of 15-19 gestational wk were studied by Northern and in situ hybridizations. The distribution pattern of the type XIII collagen mRNAs was compared with that of fibrillar collagen types I, II, and III using specific human cDNA probes for each collagen type. Northern hybridization showed the bone, cartilage, intestine, skin, and striated muscle to contain mRNAs for type XIII collagen. An intense in situ hybridization signal was obtained with the type XIII collagen cDNAs in the epidermis, hair follicles, and nail root cells of the skin, whereas the fibrillar collagen mRNAs were detected in the dermis. Cells in the intestinal mucosal layer also appeared to contain high levels of alpha 1(XIII) collagen mRNAs, but contained none of the fibrillar collagen mRNAs. In the bone and striated muscle, alpha 1(XIII) collagen mRNAs were detected in the mesenchymal cells forming the reticulin fibers of the bone marrow and endomycium. The hybridization signal obtained with the alpha 1(XIII) collagen cDNA probe in cartilaginous areas of the growth plates was similar, but less intense, to that obtained with the type II collagen probe. A clear hybridization signal was also detected at the (pre)articular surfaces and at the margins of the epiphyses, whereas it was weaker in the resting chondrocytes in the middle of the epiphyses. The brain, heart, kidney, liver, lung, placenta, spleen, testis, tendon, and thymus did not appear to contain alpha 1(XIII) collagen mRNAs.

Blotting, Northern↗

PubMed1992

Simultaneous expression of 70 kilodalton type IV collagenase and type IV collagen alpha 1 (IV) chain genes by cells of early human placenta and gestational endometrium.

BACKGROUND: In this study we used in situ hybridization to investigate the expression of the genes 70 kilodalton (kd) collagenase and the alpha 1(IV) collagen chain of type IV collagen in cells of early human placenta and gestational endometrium. EXPERIMENTAL DESIGN: The aim was to study the spatial distribution of these gene expressions within a developing tissue which possesses physiologic invasive potential. The results obtained for the 70 kd type IV collagenase mRNA expression were also compared with the immunohistochemical distribution of the corresponding antigen. RESULTS: Expression of mRNAs for these proteins was found in cells of trophoblastic columns, stromal cells of villi and in cells of decidua and endometrial stroma. The only differences between the expressions was the lower level of signals for 70 kd type IV collagenase in fibroblastic stromal cells and endothelial cells of villi and in the pericytic cells of spiral arteries. Otherwise the results for both types of mRNA were comparable. We also studied the immunohistochemical distribution of the 70 kd type IV collagenase using specific monoclonal antibodies against the enzyme. Immunohistochemistry supported well the findings obtained by in situ hybridization. CONCLUSIONS: The results indicate that the genes for the 70 kd type IV collagenase and for the alpha 1(IV) collagen chain are simultaneously active in cells of placenta and gestational endometrium and the same cells which produce type IV collagen also can produce the cleaving enzyme, the 70 kd type IV collagenase. The results also show that the cytotrophoblastic cells, which during early pregnancy invade the extracellular matrix and spiral arteries of uterine wall contain significant amount of mRNA for the 70 kd type IV collagenase. This finding supports the concept that the 70 kd type IV collagenase would be important for invasion, and in the case of this study, also for the physiologic invasion of placental cytotrophoblasts.

Amino Acid Sequence↗

PubMed1985

Intron-mediated recombination may cause a deletion in an alpha 1 type I collagen chain in a lethal form of osteogenesis imperfecta.

To understand the nature of the mutation in type I collagen genes in cells from an infant with the perinatal lethal form of osteogenesis imperfecta (type II), we cloned and sequenced almost 2 kilobases of a normal alpha 1(I) collagen gene and the corresponding region of a mutant alpha 1(I) gene from cell strain CRL 1262. The mutant gene had undergone recombination between two non-homologous introns, which resulted in the loss of three exons coding for 84 amino acids in the triple-helical domain. The deletion predicted the loss of amino acid residues surrounding and including the methionine at the junction between the CNBr peptides alpha 1(I) CB8 and alpha 1(I) CB3, a result confirmed by analysis of the cleavage peptides from the product of the mutant gene. Although large deletions from collagen genes are uncommon causes of the osteogenesis imperfecta type II phenotype, analysis of the de novo change in gene structure in this cell strain suggests that similar rearrangements may have occurred during the evolution of the large collagen genes.

Amino Acid Sequence↗

PubMed1995

Monoclonal antibody MT2 identifies the urodele alpha 1 chain of type XII collagen, a developmentally regulated extracellular matrix protein in regenerating newt limbs.

We previously described the upregulation of the MT2 antigen during urodele limb regeneration and characterized the MT2 antigen as a 310- to 325-kDa chondroitin-sulfated glycoprotein with a core protein of 285-300 kDa. In this study, we screened a newt blastema cDNA library using monoclonal antibody (mAb) MT2 and obtained a 1-kb cDNA fragment, designated Isolate (IS)-1. Subsequent screening of the same library using IS-1 cDNA as a probe provided IS-2, a 2.8-kb cDNA. IS-2 overlaps IS-1 at its 5' end, is highly homologous to a portion of the alpha 1 chain of the chicken type XII collagen cDNA (alpha 1[XII]), and spans a third of the chicken alpha 1[XII] cDNA, from the last 62 amino acids of the second A domain of von Willebrand factor to the first two repeats of the fourth fibronectin type III domain. The peptide sequence deduced from cDNA IS-2 demonstrates invariable tryptophan, leucine, threonine, and tyrosine residues that are highly conserved among all the fibronectin type III domains within IS-2 and between corresponding sequences of IS-2 and chicken alpha 1[XII]. A Northern blot showed a 10-kb band that corresponds to the size of the chicken alpha 1[XII] mRNA. A fusion gene was constructed by inserting the IS-2 cDNA downstream from the malE gene of Escherichia coli, which encodes maltose-binding protein (MBP). The isopropyl beta-D-thiogalactoside-induced fusion protein had the expected molecular weight and reacted to both mAb MT2 and rabbit anti-MBP serum. We conclude that mAb MT2 identifies the urodele alpha 1[XII]. The expression pattern of the type XII collagen gene in newt limb regenerates was examined by in situ hybridization. Type XII collagen transcripts first appeared at 3 days after amputation in cells of the basal layer of the wound epithelium. At Day 10, both the basal wound epithelial cells and the distal mesenchyme cells were highly transcriptionally active. At mid-bud and late-bud blastema stages, wound epithelium expression had decreased, whereas the mesenchyme remained strongly active in transcription and showed a tendency toward distal regionalization. Condensing cartilage showed no signal. Finally, at the late digit stage, hybridization became largely restricted to the perichondrium. The in situ results suggest a developmental role for type XII collagen in regeneration.

Amino Acid Sequence↗

PubMed1994

Assembly and sequencing of a cDNA covering the entire mouse alpha 1(IX) collagen chain.

Type IX collagen, a member of the FACIT family of collagenous proteins, contains heterotrimeric molecules of distinct alpha 1(IX), alpha 2(IX) and alpha 3(IX) chains. In this paper we describe the assembly and nucleotide sequence of a cDNA encoding the entire mouse alpha 1(IX) collagen chain. The nucleotide sequence provides for the first time the complete primary structure of the mouse chain. Knowledge of the complete structure of mouse alpha 1(IX) collagen will be useful for investigations of type IX collagen expression during normal mouse development and for the generation of transgenic mice with specific defects in this collagen.

Amino Acid Sequence↗

PubMed1989

Covalent structure of collagen: amino acid sequence of three cyanogen bromide-derived peptides from human alpha 1(V) collagen chain.

Type V collagen was prepared from human amnionic/chorionic membranes and separated into alpha 1(V) and alpha 2(V) polypeptide chains. The alpha 1(V) chain was digested with cyanogen bromide and nine peptides were obtained and purified. Three of the peptides, alpha 1(V)CB1, CB4, and CB7 having molecular weights of 5000, 8000, and 6000, respectively, were further analyzed by amino acid sequence analysis and thermolytic or tryptic digestions. CB1 contained 54 amino acids and identification of its complete sequence was aided by thermolysin digestion and isolation of two peptides, Th1 and Th2. CB4 contained 81 amino acids and sequence analysis of intact CB4 and five tryptic peptides provided us with its complete amino acid sequence. The peptide CB7 contained 67 amino acids and was cleaved into four tryptic peptides that were used for complete sequence analysis. The above results represent the first available covalent structure information on the alpha 1(V) collagen chain. These data enabled us to establish the location of these peptides within the helical structure of other collagen chains. CB4 was homologous to residues 66-145 in the collagen chain while CB1 represented residues 146-200 and CB7 was homologous with residues 201-269. This alignment was facilitated by identification of a helical collagen crossing site consisting of Hyl-Gly-His-Arg located at positions 87-90 in all collagen chains of this size thus far identified. Seventy-one percent homology (excluding Gly residues) was found between amino acids in this region of the alpha 1(XI) and of alpha 1(V) collagen chains while only 21 and 19% identity was calculated for the same region of alpha 2(V) and alpha 1(I) collagen chains, respectively.

Amino Acid Sequence↗

PubMed1983

Completion of the amino acid sequence of the alpha 1 chain from type I calf skin collagen. Amino acid sequence of alpha 1(I)B8.

The complete amino acid sequence of the 279-residue CNBr peptide CB8 from the alpha 1 chain of type I calf skin collagen is presented. It was determined by sequencing overlapping fragments of CB8 produced by Staphylococcus aureus V8 proteinase, trypsin, Endoproteinase Arg-C and hydroxylamine. Tryptic cleavages were also made specific for lysine by blocking arginine residues with cyclohexane-1,2-dione. This completes the amino acid sequence analysis of the 1054-residues-long alpha (I) chain of calf skin collagen.

Amino Acid Sequence↗

PubMed1998

Expression of the alpha 1 and alpha 2 chains of type IV collagen in the infarct zone of rat myocardial infarction.

Healing processes affect ventricular remodeling, an important prognostic factor in acute myocardial infarction (AMI). Type IV collagen, a major component of the basement membrane, has been demonstrated to appear in the infarct zone. Six type IV alpha chains, alpha 1 to alpha 6 [alpha 1(IV) to alpha 6(IV)], have been identified. We examined the expression of the alpha 1(IV), alpha 2(IV), alpha 3(IV) and alpha 5(IV) in experimental rat AMI induced by permanent ligation of the left coronary artery in male Sprague-Dawley rats. Neonatal cardiac fibroblasts cultured to reach confluency were also used to examine the hypoxic induction of the expression of these chains. Northern blotting, in situ hybridization, and immunohistochemical staining were employed to examine the alpha chain expression. With the in situ hybridization, alpha 1(IV) and alpha 2(IV) mRNA signals were observed in spindle-shaped mesenchymal cells in the intercellular spaces, in the vascular endothelial cells and in some myocytes in the normal myocardium. Signals for both alpha 1(IV) and alpha 2(IV) mRNA appeared in the spindle-shaped mesenchymal cells located between the surviving myocytes in the infarct peripheral zone at 24 h after the ligation. These signals extended into the central zone and reached the center point of the infarct 5 days after the ligation. Neither alpha 3(IV) nor alpha 5(IV) mRNA signals were observed in the infarct zone. Northern blotting demonstrated increased expressions of alpha 1(IV) and alpha 2(IV) mRNA in the infarct zone compared to the sham-operated hearts. The expression of alpha 5(IV) mRNA was weak in the sham-operated hearts but was not detected in the infarct zone. alpha 3(IV) mRNA was not expressed in the infarct zones or sham-operated hearts. In the cultured cardiac fibroblasts, a hypoxic induction of the expression of both alpha 1(IV) and alpha 2(IV) mRNA was demonstrated by Northern hybridization. Immunohistochemistry revealed alpha 1(IV) and alpha 2(IV) staining in the infarct lesion. The findings demonstrate that among the type IV collagen alpha chains examined, alpha 1(IV) and alpha 2(IV) produced by mesenchymal cells appeared in the infarct zone, suggesting that type IV collagen composed by alpha 1 and alpha 2 chains contributes to the pathological course of myocardial infarction.

Animals↗

PubMed1993

Characterization of an arginine 789 to cysteine substitution in alpha 1 (II) collagen chains of a patient with spondyloepiphyseal dysplasia.

A child with spondyloepiphyseal dysplasia congenita was shown to be heterozygous for a mutation of the COL2A1 gene that encodes the alpha 1 (II) chain of type II collagen. The alpha 1 (II) chains extracted from cartilage contained disulfide-bonded dimeric and trimeric alpha 1 (II) chains. Carboxymethylation confirmed that some of the type II collagen chains contained cysteine residues that are not normally present in alpha 1 (II) chains. Cyanogen bromide peptide mapping showed that the abnormal cysteine residue was located in the alpha 1 (II) CB10.5 peptide. Amplification products of the corresponding region of alpha 1 (II) cDNA prepared from cultured dermal fibroblasts were shown by chemical cleavage and single strand conformation polymorphism analyses to contain a sequence anomaly. DNA sequencing showed a transition of C2913T in exon 41 of one allele of the COL2A1 gene resulting in the substitution of arginine 789 by cysteine in the alpha 1 (II) chain. The mutation resulted in the loss of a MaeII cleavage site that was used to confirm that the proband was heterozygous for the mutation and that neither parent showed evidence of the mutation. The type II collagen extracted from cartilage and from chondrocytes cultured in alginate beads showed similar characteristics. Approximately a third of the type II collagen chains were mutant, and the secretion of molecules containing mutant chains was impaired. The thermal stability of the collagen extracted from cartilage was normal. This study confirmed the importance of dominant negative mutations of the COL2A1 gene in producing the spondyloepiphyseal dysplasia congenita phenotype.

Amino Acid Sequence↗