SEARCH · PubMed Health

Results for “Alternative Splicing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources

PubMed1992

Bovine amelogenin message heterogeneity: alternative splicing and Y-chromosomal gene transcription.

The amelogenins are the most abundant proteins in developing tooth enamel. Previous analyses have demonstrated that transcriptionally active genes encoding the proteins are located on both the bovine X and the bovine Y chromosomes. We report here the cloning and sequence analysis of the Y-chromosomal gene and corresponding cDNA. The Y-specific mRNA encodes a translation product in which a 21 amino acid domain has been deleted, relative to the X-specific amelogenin, resulting in loss of a structure tentatively described as a beta-spiral. There are also 13 single amino acid differences compared to the X-specific amelogenin. In addition, we have cloned and sequenced an X-chromosomal alternatively spliced amelogenin cDNA that encodes a 43 amino acid amelogenin primary translation product. Hydrophobicity analysis indicates that all analyzed amelogenin proteins have a mean hydrophilic character and the two peptides translated from alternatively spliced messages have significant increases in percentage of hydrophobic amino acids.

Amelogenin↗

PubMed1988

Absence of alternative splicing in bcr-abl mRNA in chronic myeloid leukemia cell lines.

The major consequence of the Philadelphia (Ph) translocation in chronic myeloid leukemia (CML) is the formation of a bcr-abl hybrid oncogene encoding a tumor cell-specific protein P210bcr-abl. In contrast to this, in Ph chromosome-positive acute lymphoblastic leukemia (Ph + ALL), a P190bcr-abl can be observed. This P190bcr-abl has been implicated in acute rather than chronic leukemogenesis. Therefore, it can be hypothesized that the transition from chronic to blast phase in CML is accompanied by an alternative splice in the bcr-abl mRNA, which results in a switch of the production of P210bcr-abl into P190bcr-abl. Initial S1 nuclease protection mapping supported this theory. However, this result appears to be based on an artifact in the S1 analysis. By using the polymerase chain reaction we provide evidence for the absence of alternative splicing in bcr-abl mRNA in two CML blast crisis cell lines.

Blast Crisis↗

PubMed2000

Alternatively spliced MDM2 transcripts in human breast cancer in relation to tumor necrosis and lymph node involvement.

Several short forms of alternatively spliced Murine double minute 2 (MDM2) transcripts have recently been shown to correlate with high-grade malignancy in a number of human tumors. We examined the frequency of splice variants and their correlation with clinicopathological features in 60 cases of human breast cancer. Seven short forms coexpressed with wild-type mRNA were detected by nested RT-PCR. Sequencing of all the MDM2 variants demonstrated mRNA splicing which disrupted not only the conserved p53-binding domain but also, further towards the carboxy-terminus, the conserved nuclear localization sequence and/or the acidic and zinc finger domains. There was no significant correlation between the coexpression of splice variants and tumor size, histologic type or hormone (estrogen and progesterone) receptor status. However, cases with spliced MDM2 transcripts tended to be of a more aggressive type with axillary lymph node involvement and extensive necrosis in the tumors. Although the functional significance of MDM2 variants remains obscure, we anticipate that these variants will be confirmed as a novel prognostic marker in human breast cancer.

Adenocarcinoma↗

PubMed1987

Two forms of 1B236/myelin-associated glycoprotein, a cell adhesion molecule for postnatal neural development, are produced by alternative splicing.

The structures of two rat brain-specific 1B236 mRNAs, alternative splice products from a single gene regulated differently during postnatal brain development, were deduced from full-length cDNA clones. The 626- and 582-amino acid-long encoded proteins are indistinguishable from two forms of myelin-associated glycoprotein, a cell adhesion molecule involved in axonal-glial and glial-glial interactions in postnatal brain development, particularly in myelination. The two proteins share a single membrane-spanning domain and a glycosylated N terminus but differ in the structures of their C termini. The N terminus consists of five domains related in sequence to each other and to immunoglobulin-like molecules, especially the neural cell adhesion molecule N-CAM, suggesting a common structure for cell adhesion molecules.

Aging↗

PubMed1996

Fibronectin isoform distribution in the mouse. II. Differential distribution of the alternatively spliced EIIIB, EIIIA, and V segments in the adult mouse.

The alternatively spliced EIIIB, EIIIA, and V segments of fibronectin (FN) show widespread codistribution in the mouse embryo, suggesting that EIIIB+, EIIIA+, and V+ isoforms serve to facilitate morphogenesis and organogenesis (Peters, JH, and Hynes, RO, 1996, this issue). To gain further clues to functions of these segments, we have used segment-specific anti-FN antibodies to perform immunofluorescence microscopy on tissue sections obtained from mice aged 9 to 15 weeks. Staining for each of the three spliced segments, relative to that for the total FN pool, was reduced in the adult as compared with the embryo. Anti-V antibodies produced patterns which were most similar to those obtained with anti-total FN antibodies, localizing to basement membranes, connective tissues subjacent to epithelia, walls of blood vessels, and cartilage. Anti-EIIIA antibodies produced the next most widespread pattern, which included prominent staining of the walls of blood vessels of all sizes, the lung interstitium, and smooth muscle associated with the gastrointestinal (GI), genitourinary (GU), and respiratory tracts. Although anti-EIIIB antibodies produced the faintest and most restricted pattern of staining, EIIIB+ FN could be detected in the walls of some smaller blood vessels, smooth muscle of the GI, GU, and respiratory tracts, as well as within cartilaginous structures, and eye. There were quantitative and/or qualitative differences in the staining patterns produced by the three segment-specific antibodies in a variety of tissues, including liver, cartilage, synovium, cornea, muscle, peripheral nerve, and lymph node. These findings suggest that each of the spliced segments of the FN molecule may occupy unique physical or functional positions within the extracellular matrix of the adult mouse.

Animals↗

PubMed1993

Alternative splicing gives rise to a nuclear protein tyrosine phosphatase in Drosophila.

A novel Drosophila protein tyrosine phosphatase gene (dPTP61F) undergoes alternative splicing to encode two non-receptor-like proteins of 61,000 daltons. This splice selection occurs at the 3' end of the message, altering the carboxyl termini of the encoded proteins. These carboxyl-terminal sequences govern the targeting of each protein tyrosine phosphatase either to a cytoplasmic membrane or to the nucleus. The catalytic activity of the two protein products is indistinguishable, suggesting that substrate specificity is modulated by the protein's subcellular location.

Alternative Splicing↗

PubMed1990

cDNA cloning of a dihydropyridine-sensitive calcium channel from rat aorta. Evidence for the existence of alternatively spliced forms.

Several complementary DNAs have been isolated from rat aorta cDNA libraries that encode the alpha 1 subunit of the L-type dihydropyridine-sensitive voltage-dependent calcium channel (VDCC). The clones were isolated using previously cloned rabbit skeletal and cardiac VDCC cDNAs as well as newly isolated rat aorta cDNA clones as probes. The complete nucleotide sequence of the 8305-base pair aortic alpha 1 cDNA codes for a protein of 2169 amino acids, which corresponds to an Mr of 243,615. The deduced amino acid sequence exhibits 93 and 65% amino acid identity with previously cloned rabbit cardiac and rabbit skeletal muscle dihydropyridine-sensitive VDCCs, respectively. The close identity of the aortic alpha 1 cDNA with cardiac alpha 1 cDNAs suggests that they arise from the same gene. Specific divergent areas of the aortic cDNA suggest that this cDNA represents an alternatively spliced form. We report the existence of two forms of a specific region within this aortic cDNA which also exists in cardiac tissue. This evidence supports the existence of alternative splicing for calcium channel cDNAs, a mechanism which provides diversity and potential tissue-specific isoforms of the L-type VDCC. The rat aorta alpha 1 isoform has a message size of 8.6 kilobases (kb). Rat aorta also contains additional transcripts of 12.0 and 6.5 kb. Northern blot analysis of poly(A)+ RNA from several rat tissues including heart, brain, and several smooth muscles reveals the co-existence of the 8.6- and 12.0-kb mRNA species but not the 6.5-kb species. Southern analysis of rat genomic DNA reveals a low copy number of the gene encoding this type of calcium channel.

Amino Acid Sequence↗

PubMed1993

Developmental expression and alternative splicing of chick agrin RNA.

Agrin is a synaptic basal lamina protein that has been proposed to mediate motor neuron-induced clustering of acetylcholine receptors during development of the neuro-muscular junction. The chick ciliary ganglion is a parasympathetic ganglion that contains motor neurons that project to striated and smooth muscle targets in the eye. We have examined agrin gene expression in the chick ciliary ganglion during normal embryonic development using in situ hybridization and quantitative PCR techniques. Ganglia were specifically labeled by antisense agrin cRNA probes and the density of labeling changed during development. Hybridization was most intense in sections of ganglia obtained from embryos before embryonic Day 15 (E15), declining to relatively low levels by hatching at E20. Throughout embryonic development labeling was associated with glial cells, in addition to both ciliary and choroid neurons. Measurement of agrin mRNA levels by competitive PCR showed that agrin gene expression in the ganglion increased dramatically between E8 and E10, was sustained at high levels from E10 to E14, and declined thereafter. This time course is coincident with the period of synapse formation between ganglionic neurons and their peripheral targets. Previous studies in chick CNS have shown that alternative RNA splicing of a single exon encoding 11 amino acids gives rise to an active and an inactive agrin protein. Our analysis of RNA isolated from chick ciliary ganglia demonstrated that a second, previously uncharacterized exon encoding 8 amino acids can also be spliced into the same region. Alternative splicing of both the 8- and the 11-amino-acid exons results in expression of four distinct agrin transcripts in the ganglion. Changes in the level of total agrin mRNA in the ganglion reflect developmentally regulated changes in the levels of these alternatively spliced agrin isoforms. These results demonstrate that agrin is expressed in autonomic motor neurons of the peripheral nervous system and support a wider role for agrin as a synaptogenic protein, not limited to spinal motor neurons.

Agrin↗

PubMed1997

Tissue-specific transcription start sites and alternative splicing of the parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor gene: a new PTH/PTHrP receptor splice variant that lacks the signal peptide.

The PTH/PTHrP receptor gene is expressed in bone and kidney as well as in many other tissues. Using primer extension followed by rapid cloning of amplified complementary DNA ends, we have isolated new PTH/PTHrP receptor complementary DNAs with different splicing patterns and have characterized a new upstream transcription start site. Three 5' nontranslated exons, U3, U2 and U1, located 4.8, 2.5, and 1.2 kb upstream of the exon that encodes the putative signal peptide of the classical receptor (exon S), have been characterized. Four types of splicing patterns were recognized. Type I splicing pattern is transcribed from exon U1 and is spliced to exons S and E1; this pattern was found in most tissues tested. Types II, III, and IV splicing patterns are transcribed from exon U3 and have a restricted tissue distribution. Type II splice pattern, containing exons U3, U2, and S and type III splicing pattern, containing exon U3, U2, and E1 (skipping exon S), was found only in kidney. Type IV splice pattern, containing exon U3 and S was found both in kidney and ovary. Because the type III splice variant skips exon S, translation of this splice variant initiates at a different AUG codon. The type III splice variant was weakly expressed on the cell surface of COS-7 cells, as assessed by double antibody binding assay, and no detectable ligand binding was observed on intact cells. The type III splice variant, however, increased cAMP accumulation in COS-7 cells when challenged with PTH(1-34), PTH(1-84) and hPTHrP(1-36) with EC50s that are similar to those observed in COS-7 cells expressing the type I variant but with a maximum stimulation that was lower than that observed in COS-7 cells expressing the type I variant. These data indicate low levels of cell surface expression of the type III splice variant. Treatment of COS-7 cells with tunicamycin decreased the size of the type I splice variant from a broad band of 85 kDa to a compact band of about 60 kDa. The type III splice variant did not change in size in COS-7 cells treated with tunicamycin, indicating that the type III splice variant did not undergo any glycosylation step. In conclusion, the PTH/PTHrP receptor gene uses alternate promoters in a tissue-specific manner that results in several tissue-specific alternatively spliced transcripts. One of these transcripts, the type III splice variant, is expressed in kidney and lacks the signal peptide.

Alternative Splicing↗

PubMed2004

GluR4c, an alternative splicing isoform of GluR4, is abundantly expressed in the adult human brain.

We report the cloning of human GluR4c, an alternative splicing isoform of GluR4. Similar to rodent and chick GluR4c mRNA, human GluR4c had a 113-bp insert containing a stop codon, resulting in a short C terminus. The expression of human GluR4c was widespread in the brain, and was upregulated with development in the cerebellum and cerebral cortex where the level of it was about 30% of total GluR4 mRNA in adult stage. The GluR4 subunit may play a pivotal role in regulating channel properties as well as trafficking of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors in the adult human brain.

Adult↗

PubMed1992

Expression of the LH/CG receptor gene in rat ovarian tissue is regulated by an extensive alternative splicing of the primary transcript.

Luteinizing hormone/chorionic gonadotropin (LH/CG) receptor complementary DNA (cDNA) isoforms were amplified using pseudopregnant rat ovarian total RNA as a template and the primers reaching over the coding regions at both ends in a reverse transcriptase-polymerase chain reaction (RT-PCR). Agarose gel electrophoresis of the PCR products revealed three bands corresponding to about 2.1, 2.0 and 1.8 kilobases (kb). Subcloning of pooled PCR products into EcoRI site of pUCBM20 resulted in 167 clones, from which five different restriction patterns were obtained by digestion with EcoRI and HaeIII. One clone of each was further characterized. It could be predicted from the nucleotide sequences that the clone rLHR2100 encoded a full-length receptor (a 674 amino acid mature protein), the clone rLHR2075 lacked part of exon IX (nucleotides 693-717) and encoded a truncated 225 amino acid mature protein, the clone rLHR1950 lacked exons III and IV (nucleotides 246-395) and encoded a nearly full-length protein (a 624 amino acid mature protein), and the clones rLHR1834 and rLHR1759 lacked the same part of exon XI (nucleotides 960-1225), with exon V (nucleotides 396-470) also absent in the latter, the deletion in exon XI leading both these clones to premature termination. The clone rLHR1834 encoded a 316 amino acid mature protein and rLHR1759 a 291 amino acid mature protein, respectively. The sequence data suggest that all of these isoforms contain the putative signal sequence and are derived from a single copy gene via alternative splicing. These results point further to the fact that the expression of the 90 kDa LH/CG receptor is regulated via an extensive alternative splicing of the receptor gene primary transcript.

Alleles↗

PubMed1990

The murine complement receptor gene family. IV. Alternative splicing of Cr2 gene transcripts predicts two distinct gene products that share homologous domains with both human CR2 and CR1.

The murine Cr2 gene encodes at least two related proteins. The first of these is predicted to include 1408 amino acids from a transcript including 4224 coding nucleotides. This protein is predicted to contain 21 60-amino acid repeats plus those residues encoding transmembrane and cytoplasmic regions for a total peptide m.w. of 155,307. The first six of these repeats are similar to human CR1 in sequence and organization. The second protein is encoded by an alternatively spliced Cr2 transcript that is lacking those sequences which encode the first six 60-amino acid repeats of the larger protein. This second, smaller protein, encoded by a transcript of 3096 coding nucleotides, is predicted to include 15 60-amino acid repeats, plus the transmembrane and cytoplasmic regions. This smaller protein contains 1032 amino acids for a peptide m.w. of 113,328. This second protein is extremely homologous in size and sequence to human CR2. Both proteins share the same signal sequence for membrane insertion. DNA sequence analysis, RNA protection studies and genomic phage mapping indicate the transcripts which encode these proteins are derived from the Cr2 gene via alternative splicing.

Amino Acid Sequence↗

PubMed2003

Alternative splicing of Rac1 generates Rac1b, a self-activating GTPase.

Rac1b was recently identified in malignant colorectal tumors as an alternative splice variant of Rac1 containing a 19-amino acid insertion next to the switch II region. The structures of Rac1b in the GDP- and the GppNHp-bound forms, determined at a resolution of 1.75 A, reveal that the insertion induces an open switch I conformation and a highly mobile switch II. As a consequence, Rac1b has an accelerated GEF-independent GDP/GTP exchange and an impaired GTP hydrolysis, which is restored partially by GTPase-activating proteins. Interestingly, Rac1b is able to bind the GTPase-binding domain of PAK but not full-length PAK in a GTP-dependent manner, suggesting that the insertion does not completely abolish effector interaction. The presented study provides insights into the structural and biochemical mechanism of a self-activating GTPase.

Alternative Splicing↗

PubMed2001

[The alternative splicing & expression of fibronectin IIIcs segment and its relationship with wound healing].

Fibronectin is an important large adhesive glycoprotein of the extracellular matrix, which is alternatively spliced in three regions, designated EIIIA, EIIIB and IIIcs respectively. IIIcs contains two binding domains for a variety of cell surface and extracellular ligands. Through this multiplicity of adhesive activities, IIIcs can fulfill key roles in a broad spectrum of physiological processes, such as cell spreading and migration, differentiation and embryogenesis, wound healing, malignant transformation and metastasis, etc. Here, we will discuss the structure, biological property, and function of IIIcs splicing variants and its forensic applications.

Alternative Splicing↗

PubMed2001

Genomic organisation and alternative splicing of mouse and human thioredoxin reductase 1 genes.

BACKGROUND: Thioredoxin reductase (TR) is a redox active protein involved in many cellular processes as part of the thioredoxin system. Presently there are three recognised forms of mammalian thioredoxin reductase designated as TR1, TR3 and TGR, that represent the cytosolic, mitochondrial and novel forms respectively. In this study we elucidated the genomic organisation of the mouse (Txnrd1) and human thioredoxin reductase 1 genes (TXNRD1) through library screening, restriction mapping and database mining. RESULTS: The human TXNRD1 gene spans 100 kb of genomic DNA organised into 16 exons and the mouse Txnrd1 gene has a similar exon/intron arrangement. We also analysed the alternative splicing patterns displayed by the mouse and human thioredoxin reductase 1 genes and mapped the different mRNA isoforms with respect to genomic organisation. These isoforms differ at the 5' end and encode putative proteins of different molecular mass. Genomic DNA sequences upstream of mouse exon 1 were compared to the human promoter to identify conserved elements. CONCLUSIONS: The human and mouse thioredoxin reductase 1 gene organisation is highly conserved and both genes exhibit alternative splicing at the 5' end. The mouse and human promoters share some conserved sequences.

Journal Article↗

PubMed1995

The family of LAMP-2 proteins arises by alternative splicing from a single gene: characterization of the avian LAMP-2 gene and identification of mammalian homologs of LAMP-2b and LAMP-2c.

The two lysosome-associated membrane proteins, LAMP-1 and LAMP-2, are major integral membrane proteins of the lysosomes. They also occur in the plasma membrane, where they have been discovered independently as principal lactosaminoglycan-bearing glycoproteins and as tumor antigens. Avian LAMP-2 has recently been shown to be encoded by at least three transcripts resulting in variant transmembrane and cytoplasmic domains (Hatem et al., 1995). We report isolation and characterization of chicken genomic clones indicating that the three transcripts are the result of alternative splicing of a single LAMP-2 gene. Only a single LAMP-2, homologous to chicken LAMP-2a, has been described in mammals. To ascertain whether multiple forms of LAMP-2 also occur in mammals, we cloned cDNAs encoding LAMP-2 variants homologous to avian LAMP-2b and LAMP-2c from mouse brain cDNA libraries. Thus, the family of LAMP-2 proteins is conserved from bird to mammals and the diversity is generated by alternative splicing of a single LAMP-2 gene.

Amino Acid Sequence↗

PubMed1995

Alternative splicing of amelogenins.

Amelogenins comprise as much as 90% of the protein in the developing enamel matrix. Separating amelogenins by gel electrophoresis reveals a complex of polypeptides with apparent mobilities ranging from low molecular weight species on up to 28,000 Daltons. A major objective of our research is determine the extent to which alternative RNA splicing contributes to this heterogeneity. We have cloned seven alternatively spliced mouse amelogenin mRNAs. The predicted translation products of these messages are 194, 180, 156, 141, 74, 59, and 44 amino acids in length. The 194 residue amelogenin is the only mouse amelogenin to include a polypeptide segment encoded by exon 4, which has a deduced amino acid sequence of KSHSQAINTDRTAL. Antibodies were raised against synthetic exon 4 encoded polypeptides and used to immunostain histologic tooth sections. These data indicate that alternatively spliced amelogenin mRNAs are translated into protein and secreted into the enamel matrix.

Alternative Splicing↗

PubMed2001

Genomic organization and alternative splicing of the human and mouse RPTPrho genes.

BACKGROUND: Receptor protein tyrosine phosphatase rho (RPTPrho, gene symbol PTPRT) is a member of the type IIB RPTP family. These transmembrane molecules have been linked to signal transduction, cell adhesion and neurite extension. The extracellular segment contains MAM, Ig-like and fibronectin type III domains, and the intracellular segment contains two phosphatase domains. The human RPTPrho gene is located on chromosome 20q12-13.1, and the mouse gene is located on a syntenic region of chromosome 2. RPTPrho expression is restricted to the central nervous system. RESULTS: The cloning of the mouse cDNA, identification of alternatively spliced exons, detection of an 8 kb 3'-UTR, and the genomic organization of human and mouse RPTPrho genes are described. The two genes are comprised of at least 33 exons. Both RPTPrho genes span over 1 Mbp and are the largest RPTP genes characterized. Exons encoding the extracellular segment through the intracellular juxtamembrane 'wedge' region are widely spaced, with introns ranging from 9.7 to 303.7 kb. In contrast, exons encoding the two phosphatase domains are more tightly clustered, with 15 exons spanning approximately 60 kb, and introns ranging in size from 0.6 kb to 13.1 kb. Phase 0 introns predominate in the intracellular, and phase 1 in the extracellular segment. CONCLUSIONS: We report the first genomic characterization of a RPTP type IIB gene. Alternatively spliced variants may result in different RPTPrho isoforms. Our findings suggest that RPTPrho extracellular and intracellular segments originated as separate modular proteins that fused into a single transmembrane molecule during a later evolutionary period.

Journal Article↗