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Results for “Gene Components”

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At least 19 recordsLinked to original sources

PubMed2000

Expression of telomerase component genes in hepatocellular carcinomas.

The aim of the study was to clarify the role of telomerase component genes in hepatocarcinogenesis and to examine both the relationship between the expression of telomerase component genes and histological differentiation in hepatocellular carcinoma (HCC) and the relationship between expression levels of telomerase component genes and telomerase activity in HCCs. Telomerase is a ribonucleoprotein enzyme composed of a template RNA and several proteins. Recently, three such telomerase component genes have been identified: human telomerase reverse transcriptase (hTERT); human telomerase RNA component (hTERC); and telomerase-associated protein 1 (TEP1). The expression of these components was evaluated in 34 HCCs and 24 non-cancerous liver tissues by reverse transcriptase-polymerase chain reaction (RT-PCR). Expression of hTERT mRNA was detected in most HCCs, but not in the non-cancerous tissues (P<0.01). Expression of hTERC was detected in both HCCs and non-cancerous tissues, but the expression level in HCCs was higher than that in non-cancerous tissues (P<0.01) and tended to increase as histological differentiation became less marked. The expression level of hTERT mRNA correlated with relative telomerase activity (P<0.01). These results suggest that telomerase reactivation during hepatocarcinogenesis might be regulated by only hTERT and an increase in telomerase activity level in tumour progression might be regulated by both hTERT and hTERC.

Adult↗

PubMed1999

Renin-angiotensin system component gene polymorphism in Japanese bronchial asthma patients.

The influence of renin-angiotensin system (RAS) component gene polymorphism in the pathogenesis of bronchial asthma was investigated in an association study involving 119 bronchial asthma patients and 208 control subjects. The selected RAS polymorphisms were angiotensinogen (Agt) T235/M235 and angiotensin I-converting enzyme (ACE) insertion/deletion (I/D). The control allelic frequencies of the Agt T235/M235 (0.84/0.16) and ACE I/D (0.63/0.37) in this study were similar to the previous reports in Japanese normal population. The allelic frequencies of the Agt T235/M235 (0.84/0.16) and ACE I/D (0.65/ 0.35) among the asthma patients were not significantly different from those among the control subjects. There was no association between severity of bronchial asthma and the selected RAS component gene polymorphism. From these data, we conclude that in the Japanese population, the RAS component gene polymorphism is not associated with increased risk for bronchial asthma.

Adult↗

PubMed1990

Efficient transcription of the glycolytic gene ADH1 and three translational component genes requires the GCR1 product, which can act through TUF/GRF/RAP binding sites.

Glycolytic gene expression in Saccharomyces cerevisiae is thought to be activated by the GCR and TUF proteins. We tested the hypothesis that GCR function is mediated by TUF/GRF/RAP binding sites (UASRPG elements). We found that UASRPG-dependent activation of a heterologous gene and transcription of ADH1, TEF1, TEF2, and RP59 were sensitive to GCR1 disruption. GCR is not required for TUF/GRF/RAP expression or in vitro DNA-binding activity.

Alcohol Dehydrogenase↗

PubMed1997

Characterization of the human secretory component gene promoter.

Secretory Component (SC) is a receptor molecule implicated in the transepithelial transport of polymeric immunoglobulins. We have cloned and characterized the first exon, part of the first intron and 3500 bp of the upstream region of the gene and determined the transcription initiation region. A GC rich region immediately upstream of the transcription start region is interrupted by a potential TATA-box (TTTAA) at position -28. Promoter activity was demonstrated in transient transfection experiments in HepG2 and HeLa cells. The smallest fragment still showing transcriptional activity contains 48 bp of SC promoter. A number of putative recognition sites for transcription factors possibly involved in the regulation of SC transcription by steroids, peptide hormones and cytokines were found in the upstream region.

Base Sequence↗

PubMed1998

Four ubiquitously expressed genes, RD (D6S45)-SKI2W (SKIV2L)-DOM3Z-RP1 (D6S60E), are present between complement component genes factor B and C4 in the class III region of the HLA.

The association of the HLA class III region with many diseases motivates the investigation of unidentified genes in the 30-kb segment between complement component genes Bf and C4. RD, which codes for a putative RNA binding protein, is 205 bp downstream of Bf. SKI2W (HGMW-approved symbol SKIV2L), a DEVH-box gene probably involved in RNA turnover, is 171 bp downstream of RD (HGMW-approved symbol D6S45). RP1 (HGMW-approved symbol D6S60E) is located 611 bp upstream of C4. The DNA sequence between human RD and RP1 was determined and the exon-intron structure of SKI2W elucidated. SKI2W consists of 28 exons. The putative RNA helicase domain of Ski2w is encoded by 9 exons. Further analysis of the 2.5-kb intergenic sequence between SKI2W and RP1 led to the discovery of DOM3Z. The full-length cDNA sequence of DOM3Z encodes 396 amino acids with a leucine zipper motif. Dom3z-related proteins are present in simple and complex eukaryotes. In Caenorhabditis elegans, Dom3z-related protein could be involved in the development of germ cells. Human RD-SKI2W and DOM3Z-RP1 are arranged as two head-to-head oriented gene pairs with unmethylated CpG sequences at the common 5' regulatory region of each gene pair. The ubiquitous expression pattern suggests that these four genes are probably housekeeping genes.

Amino Acid Sequence↗

PubMed1986

The human C-reactive protein gene (CRP) and serum amyloid P component gene (APCS) are located on the proximal long arm of chromosome 1.

The genes encoding two pentraxins, C-reactive protein (CRP) and serum amyloid P component (SAP), are located on the proximal long arm of human chromosome 1. Mapping of the CRP and SAP genes between the centromere and band q32 was achieved by Southern blot analysis of DNA from a panel of human X Chinese hamster somatic cell hybrids carrying defined fragments of human chromosome 1. Both genes were localized more precisely between bands q12 and q23 by in situ hybridization to human metaphase chromosomes.

Animals↗

PubMed2002

Virulence control in group A Streptococcus by a two-component gene regulatory system: global expression profiling and in vivo infection modeling.

Two-component gene regulatory systems composed of a membrane-bound sensor and cytoplasmic response regulator are important mechanisms used by bacteria to sense and respond to environmental stimuli. Group A Streptococcus, the causative agent of mild infections and life-threatening invasive diseases, produces many virulence factors that promote survival in humans. A two-component regulatory system, designated covRS (cov, control of virulence; csrRS), negatively controls expression of five proven or putative virulence factors (capsule, cysteine protease, streptokinase, streptolysin S, and streptodornase). Inactivation of covRS results in enhanced virulence in mouse models of invasive disease. Using DNA microarrays and quantitative RT-PCR, we found that CovR influences transcription of 15% (n = 271) of all chromosomal genes, including many that encode surface and secreted proteins mediating host-pathogen interactions. CovR also plays a central role in gene regulatory networks by influencing expression of genes encoding transcriptional regulators, including other two-component systems. Differential transcription of genes influenced by covR also was identified in mouse soft-tissue infection. This analysis provides a genome-scale overview of a virulence gene network in an important human pathogen and adds insight into the molecular mechanisms used by group A Streptococcus to interact with the host, promote survival, and cause disease.

Animals↗

PubMed2002

The polymorphism of telomerase RNA component gene in patients with systemic sclerosis.

BACKGROUND: The molecular basis of senescence and immortalization is not still understood, but one hypothesis for which there has recently been much evidence involves the shortening of telomeres. It can be hypothesized that abnormalities of telomerase contribute to the emergence of abnormal fibroblast clones in systemic sclerosis (SSc). OBJECTIVES: To study possible telomere abnormalities with respect to polymorphism of the telomerase RNA component gene. METHODS: Fifty-three patients with SSc and 98 normal controls were studied. Polymerase chain reaction was used to amplify 598 bp of the telomerase RNA component gene. Amplified fragments were digested with restriction enzyme BsrDI. RESULTS: The frequency of the A allele in SSc (41.5%) showed no significant difference from that in the normal controls (32.1%). The frequency of the A/A alleles in SSc (18.9%) was significantly higher than in normal controls (5.1%), compared with G/G (35.8% and 40.8%, respectively; P < 0.02), G/A (45.3% and 54.1%, respectively; P < 0.01) and G/G plus G/A (81.1% and 94.9%, respectively; P < 0.01). CONCLUSIONS: These results showed the possible involvement of a telomerase abnormality in the emergence of abnormal fibroblast clones in SSc skin-derived fibroblasts.

Adolescent↗

PubMed1994

Co-expression of renin-angiotensin system component genes in human atrial tissue.

OBJECTIVES: To detect co-expression of genes coding for components of the renin-angiotensin system and investigate the potential for variation in the level of angiotensin converting enzyme (ACE) gene expression in the right atrial appendage of patients undergoing heart surgery. DESIGN: The right atrial appendage was collected at the time of surgery from 30 randomly chosen patients and was rapidly frozen in liquid nitrogen prior to extraction of messenger (m)RNA. Surgical samples of heart valve (n = 6) and papillary muscle (n = 3) were also examined. METHODS: Aliquots of purified mRNA were reverse-transcribed for analysis of gene expression by a polymerase chain reaction amplification assay. Primers specific for angiotensinogen, renin, ACE, cardiac chymase, atrial natriuretic peptide, glyceraldehyde-3-phosphate dehydrogenase, adenosine deaminase and the transferrin receptor were used for a qualitative analysis of co-expression of these genes within the same sample. In a subgroup of eight patients, a quantitative comparison of the relative levels of ACE gene expression was performed using a competitive polymerase chain reaction. RESULTS: Angiotensinogen and ACE expression were detected in all atrial, valve and ventricular samples examined, at levels similar to those of 'housekeeping' genes such as the transferrin receptor. Atrial renin and chymase expression were more difficult to detect, being demonstrable in only 70 and 63% of the samples, respectively. Higher levels of chymase were detected in ventricular samples than in atrial tissues. A quantitative analysis of ACE expression in eight atrial samples provided evidence of interindividual variation in the relative level of atrial ACE expression. CONCLUSIONS: The essential components of the renin-angiotensin system are co-expressed at a low level in the right atrial appendage and are detectable in other regions of the human heart. Renin and chymase genes are expressed at a lower level than the angiotensinogen and ACE genes and exhibit regional differences in expression. Interindividual variation in the relative level of ACE expression can be detected by a competitive polymerase chain reaction.

Angiotensinogen↗

PubMed1996

Mosaic type of the nontoxic-nonhemaggulutinin component gene in Clostridium botulinum type A strain isolated from infant botulism in Japan.

The gene encoding the nontoxic-nonhemaggulutinin (NTNH) component was amplified by the PCR technique using two primer sets and the DNA template from Clostridium botulinum type A strain 7I03-H isolated from infant botulism in Japan. The nucleotide sequence revealed that the NTNH gene was composed of 1,193 amino acids with a molecular weight of 130868.08. Furthermore, the N-terminal half side and C-terminal half side of the NTNH component were similar to the NTNH component of type C and type A, respectively. These results indicate that the NTNH component gene codes the mosaic NTNH component composed of type A and type C. The hemaggulutinin gene, aha, and ORF-22 gene, orf-22a, were undetectable in the region upstream of the NTNH component gene, ant. Therefore, orf-22a is not thought to play a key role in the expression of botulinum type A progenitor toxin gene.

Amino Acid Sequence↗

PubMed2001

Androgen-receptor-specific DNA binding to an element in the first exon of the human secretory component gene.

Androgens and glucocorticoids are steroid hormones, which exert their effects in vivo by binding and activating their cognate receptors. These intracellular receptors are transcription factors that can bind specific DNA sequences, called hormone response elements, located near the target genes. Although the androgen receptor (AR) and the glucocorticoid receptor (GR) bind the same consensus DNA sequence, androgen-specific responses can be achieved by non-conventional androgen response elements (AREs). Here we determine the specificity mechanism of such a selective element recently identified in the first exon of the human gene for secretory component (sc ARE). This sc ARE consists of two receptor-binding hexamers separated by three nucleotides. The DNA-binding domains of the AR and GR both bind the sc ARE, but, although the AR fragment dimerizes on the element, the GR fragment does not. Comparing the affinities of the DNA-binding domains for mutant forms of the sc ARE revealed that dimeric GR binding is actively excluded by the left hexamer and more precisely by the presence of a G residue at position -3, relative to the central spacer nucleotide. Inserting a G at this position changed a non-selective element into an androgen-selective one. We postulate that the AR recognizes the sc ARE as a direct repeat of two 5'-TGTTCT-3'-like core sequences instead of the classical inverted repeat. Direct repeat binding is not possible for the GR, thus explaining the selectivity of the sc ARE. This alternative dimerization by the AR on the sc ARE is also indicated by the DNA-binding characteristics of receptor fragments in which the dimerization interfaces were swapped. In addition, the flanking and spacer sequences seem to affect the functionality of the sc ARE.

Animals↗

PubMed2005

Central role of a bacterial two-component gene regulatory system of previously unknown function in pathogen persistence in human saliva.

The molecular genetic mechanisms used by bacteria to persist in humans are poorly understood. Group A Streptococcus (GAS) causes the majority of bacterial pharyngitis cases in humans and is prone to persistently inhabit the upper respiratory tract. To gain information about how GAS survives in and infects the oropharynx, we analyzed the transcriptome of a serotype M1 strain grown in saliva. The dynamic pattern of changes in transcripts of genes [spy0874/0875, herein named sptR and sptS (sptR/S), for saliva persistence] encoding a two-component gene regulatory system of unknown function suggested that SptR/S contributed to persistence of GAS in saliva. Consistent with this idea, an isogenic nonpolar mutant strain (DeltasptR) was dramatically less able to survive in saliva compared with the parental strain. Iterative expression microarray analysis of bacteria grown in saliva revealed that transcripts of several known and putative GAS virulence factor genes were decreased significantly in the DeltasptR mutant strain. Compared with the parental strain, the isogenic mutant strain also had altered transcripts of multiple genes encoding proteins involved in complex carbohydrate acquisition and utilization pathways. Western immunoblot analysis and real-time PCR analysis of GAS in throat swabs taken from humans with pharyngitis confirmed the findings. We conclude that SptR/S optimizes persistence of GAS in human saliva, apparently by strategically influencing metabolic pathways and virulence factor production. The discovery of a genetic program that significantly increased persistence of a major human pathogen in saliva enhances understanding of how bacteria survive in the host and suggests new therapeutic strategies.

Bacteria↗

PubMed1992

Molecular cloning and nucleotide sequence of leukocidin F-component gene (lukF) from methicillin resistant Staphylococcus aureus.

A lukF gene encoding F-component of Staphylococcal leukocidin from methicillin resistant Staphylococcus aureus (MRSA) was cloned. The nucleotide sequence of lukF gene was determined. The sequence data have revealed an open reading frame, which encodes a polypeptide with 323 amino acid residues. Inspection of the amino acid sequence deduced from nucleotide sequence of lukF and that from F-component of leukocidin from S. aureus V8 clarified that pre-matured F-component contains a typical signal peptide at the NH2 terminus and ATG starting codon for pre-matured F-component was present one base downstream to the TGA which is translation termination codon for S-component of leukocidin [A. Rahman et al. (1991) Biochem. Biophys. Res. Commun. 181, 138-144]. The nucleotide sequence of 5'-flanking region of lukF showed the presence of the consensus sequence of ribosome binding site in the internal region of the structural gene of S-component. The lukF was transcribed in the same direction as that of lukS. No Pribnow box can be discerned in the intercistronic region between the lukS and lukF genes. The amino acid sequence homology between S- and F-components was 31%. F-component was expressed in Escherichia coli DH5 alpha harboring plasmid pFRK92 which contained lukF gene.

Amino Acid Sequence↗

PubMed2006

Expression microarray and mouse virulence analysis of four conserved two-component gene regulatory systems in group a streptococcus.

Group A streptococcus (GAS) is a gram-positive human bacterial pathogen that causes diseases ranging from relatively mild epithelial cell surface infections to life-threatening invasive episodes. Much is known about the extracellular molecules that contribute to host-pathogen interactions, but in contrast, far less information is available about regulatory genes that control the expression of individual or multiple GAS virulence factors. The eight GAS genomes that have been sequenced have 12 conserved two-component gene regulatory systems (TCSs), but only 3 of these 12 have been studied in detail. Using an allelic replacement strategy with a nonpolar cassette, we inactivated the response regulator of four TCSs that have only weak homology with TCS genes of known or inferred function in other bacteria. The mutant strains were analyzed by expression microarray analysis at four time points and tested in two mouse infection models. Each TCS influenced expression (directly or indirectly) of 12 to 41% of all chromosomal genes, as assessed by growth in Todd-Hewitt broth and a custom Affymetrix GeneChip. None of the isogenic mutant strains was significantly altered for mouse virulence based on intraperitoneal inoculation. Similarly, compared to the wild-type strain, there was no significant difference in skin lesion size for three of the four mutants. In contrast, the DeltaM5005_Spy_0680 mutant strain produced significantly larger abscesses after subcutaneous inoculation into mice, consistent with a hypervirulence phenotype. The mutant strain had significantly higher in vitro expression of several proven and putative virulence genes, including scpA, encoding a peptidase that inactivates complement protein C5a. Together, the data provide new information about previously uncharacterized GAS TCSs.

Animals↗

PubMed2001

Alteration of the adrenomedullin receptor components gene expression associated with the blood pressure in pregnancy-induced hypertension.

Adrenomedullin (AM) is a potent vasodilator. Pregnancy-induced hypertension (PIH) is a common cause of maternal or fetal mortality. We measured the changes of adrenomedullin receptor components gene expression, receptor activity-modifying protein 2 (RAMP2) and calcitonin receptor-like receptor (CRLR), at feto-maternal tissues in human normotensive pregnant women and pregnancy-induced hypertensive women by Northern blot analysis. Samples of the placenta, uterine muscle, umbilical artery, and fetal membranes were obtained from each patient under informed consent. RAMP2 mRNA significantly decreased in the umbilical artery (54%, P < 0.01) and uterus (53%, P < 0.01) of the patients with PIH. CRLR mRNA also significantly decreased in both tissues of the patients with PIH. On the other hand, the RAMP2 mRNA was significantly increased in the fetal membrane of the patients with PIH. In addition, there was a significant negative correlation between the RAMP2 mRNA levels in the umbilical artery (systolic; r = -0.623, P < 0.01, diastolic; r = -0.552, P < 0.01) and uterine muscle (systolic; r = -0.563, P < 0.01, diastolic; r = -0.553, P< 0.01) and blood pressure. However, there was no correlation between the mRNA level and blood pressure in fetal membrane and placenta, suggesting that there is no close relationship to the pathogenesis in PIH. These findings suggested that the reduced expression of adrenomedullin receptor component in umbilical artery and uterus may have some role in PIH.

Adult↗

PubMed1993

Gene components responsible for discrete substrate specificity in the metabolism of biphenyl (bph operon) and toluene (tod operon).

bph operons coding for biphenyl-polychlorinated biphenyl degradation in Pseudomonas pseudoalcaligenes KF707 and Pseudomonas putida KF715 and tod operons coding for toluene-benzene metabolism in P. putida F1 are very similar in gene organization as well as size and homology of the corresponding enzymes (G. J. Zylstra and D. T. Gibson, J. Biol. Chem. 264:14940-14946, 1989; K. Taira, J. Hirose, S. Hayashida, and K. Furukawa, J. Biol. Chem. 267:4844-4853, 1992), despite their discrete substrate ranges for metabolism. The gene components responsible for substrate specificity between the bph and tod operons were investigated. The large subunit of the terminal dioxygenase (encoded by bphA1 and todC1) and the ring meta-cleavage compound hydrolase (bphD and todF) were critical for their discrete metabolic specificities, as shown by the following results. (i) Introduction of todC1C2 (coding for the large and small subunits of the terminal dioxygenase in toluene metabolism) or even only todC1 into biphenyl-utilizing P. pseudoalcaligenes KF707 and P. putida KF715 allowed them to grow on toluene-benzene by coupling with the lower benzoate meta-cleavage pathway. Introduction of the bphD gene (coding for 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase) into toluene-utilizing P. putida F1 permitted growth on biphenyl. (ii) With various bph and tod mutant strains, it was shown that enzyme components of ferredoxin (encoded by bphA3 and todB), ferredoxin reductase (bphA4 and todA), and dihydrodiol dehydrogenase (bphB and todD) were complementary with one another. (iii) Escherichia coli cells carrying a hybrid gene cluster of todClbphA2A3A4BC (constructed by replacing bphA1 with todC1) converted toluene to a ring meta-cleavage 2-hydroxy-6-oxo-hepta-2,4-dienoic acid, indicating that TodC1 formed a functional multicomponent dioxygenase associated with BphA2 (a small subunit of the terminal dioxygenase in biphenyl metabolism), BphA3, and BphA4.

Base Sequence↗

PubMedDate not supplied

Altered extracellular matrix component gene expression in murine polycystic kidney.

The DBA/2FG-pcy mouse has a form of slowly progressive kidney disease that appears similar in many respects to that seen in the autosomal dominant form of human polycystic kidney disease. This study was designed to assess how the expression of extracellular matrix component genes is regulated in a model of murine polycystic kidney disease and control DBA/2 mice at 8, 16, and 30 weeks of age. The mRNA levels encoding for collagen IV, the B1 and B2 chains of laminin, heparan sulfate proteoglycan, fibronectin, and collagens I and III increased with the progression of cystic lesions in the kidney of DBA/2FG-pcy mice. At 30 weeks of age, mRNA levels for collagen IV, laminin B1 and B2, heparan sulfate proteoglycan, fibronectin, and collagens I and III were increased 8.1-fold, 7.0-fold, 7.0-fold, 9.8-fold, 7.0-fold, 5.5-fold, and 5.4-fold, respectively, compared to those of control DBA/2 mice. An immunofluorescence study revealed the irregular staining for collagen IV, laminin, heparan sulfate proteoglycan, and collagens I and III around the cysts. These data suggest that changes in the expression of basement membrane components and interstitial collagens are associated with the development of polycystic kidney disease.

Animals↗

PubMed1979

Expression of RNA polymerase and ribosome component genes in Escherichia coli mutants having conditionally defective RNA polymerases.

The expression of the genes coding for the beta and beta' subunits of RNA polymerase, ribosomal RNA, ribosomal proteins, and beta-galactosidase was investigated in strains carrying conditionally lethal mutations affecting either RNA polymerase core assembly or RNA polymerase enzyme activity. The mutant strain XH56 produces a temperature-sensitive beta' subunit and at 42 degrees C is defective in RNA chain initiation; consequently, little or no transcription occurs at the restrictive temperature. A partial restriction, produced by shifting the strain to 39 degrees C, resulted in a rapid fivefold increase in the transcription of the rpoB and C genes and in the synthesis of the beta- and beta'-subunit proteins for which they code. The RNA polymerase assembly-defective strains A2R7 and TS4 exhibited a 1.5- to 2-fold increase in the transcription of the rpoB and C genes and in the synthesis of beta- and beta-subunit proteins after prolonged restriction. These results demonstrate (i) that regulation of the synthesis of the beta- and beta-RNA polymerase subunits is under these conditions primarily transcriptional rather than translational, and (ii) that a stimulation of rpoB and C gene expression results from a restriction on RNA synthesis caused by either RNA polymerase inactivation or inhibition of its assembly. During restriction of the mutant strains, the transcription of the ribosome component genes exhibited patterns which were similar to transcription of the rpoB and C genes, supporting the evidence that genes coding for RNA polymerase are cotranscribed with ribosomal protein genes; transcription of the lacZ gene was observed to decrease concomitant with the stimulation of the rpoB and C genes.

Bacterial Proteins↗