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Differential Splicing (differential + splicing)

Distribution by Scientific Domains

Life Sciences	55%
Chemistry	22%

Selected Abstracts

Interleukin-5 does not influence differential transcription of transmembrane and soluble isoforms of IL-5R, in vivo

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 3 2006
Jonas Byström
Abstract:, Interleukin-5 (IL-5) promotes signal transduction and expansion of eosinophil colonies in bone marrow via interactions with its heterodimeric receptor (IL-5R). Two variants encoding soluble forms of the alpha subunit (sIL-5R,) have been described, although the signals promoting and/or limiting differential transcription remain to be clarified. Objectives:,Our intent was to explore the role of IL-5 in regulating differential transcription of these splice variants in vivo. Methods:,We have designed a quantitative reverse transcriptase-polymerase chain reaction assay to detect transcripts encoding the transmembrane, soluble 1 and 2 forms of IL-5R, in two strains of wild-type (BALB/c and C57BL/6) and corresponding IL-5 gene-deleted mice. Wild-type mice respond to S. mansoni infection with a gradual increase in serum IL-5 and eosinophilia, which is not observed in IL-5 gene-deleted mice. Results and conclusions:,We find that IL-5 is not necessary for differential splicing to occur in vivo, as all three forms of the IL-5R, are detected in both strains of IL-5 gene-deleted mice, with ratios of transcript expression (transmembrane : soluble 1 : soluble 2) that were indistinguishable from their wild-type counterparts. Differential splicing does vary markedly between strains, potentially because of local effects of strain-specific polymorphisms. [source]

Localization and functional characterization of the human NKCC2 isoforms

ACTA PHYSIOLOGICA, Issue 3 2010
I. Carota
Abstract Aim:, Salt reabsorption across the apical membrane of cells in the thick ascending limb (TAL) of Henle is primarily mediated by the bumetanide-sensitive Na+/K+/2Cl, cotransporter NKCC2. Three full-length splice variants of NKCC2 (NKCC2B, NKCC2A and NKCC2F) have been described. The NKCC2 isoforms have specific localizations and transport characteristics, as assessed for rabbit, rat and mouse. In the present study, we aimed to address the localization and transport characteristics of the human NKCC2 isoforms. Methods:, RT-PCR, in situ hybridization and uptake studies in Xenopus oocytes were performed to characterize human NKCC2 isoforms. Results:, All three classical NKCC2 isoforms were detected in the human kidney; in addition, we found splice variants with tandem duplicates of the variable exon 4. Contrary to rodents, in which NKCC2F is the most abundant NKCC2 isoform, NKCC2A was the dominant isoform in humans; similarly, isoform-specific in situ hybridization showed high expression levels of human NKCC2A along the TAL. Compared to NKCC2B and NKCC2F, human NKCC2A had the lowest Cl, affinity as determined by 86Rb+ uptake studies in oocytes. All NKCC2 isoforms were more efficiently inhibited by bumetanide than by furosemide. A sequence analysis of the amino acids encoded by exon 4 variants revealed high similarities between human and rodent NKCC2 isoforms, suggesting that differences in ion transport characteristics between species may be related to sequence variations outside the highly conserved sequence encoded by exon 4. Conclusion:, The human NKCC2 is an example of how differential splicing forms the basis for a diversification of transporter protein function. [source]

Interleukin-5 does not influence differential transcription of transmembrane and soluble isoforms of IL-5R, in vivo

Identification of novel splice variants of the human catalytic subunit c, of cAMP-dependent protein kinase

FEBS JOURNAL, Issue 19 2001
Sigurd Ørstavik
Four different isoforms of the catalytic subunit of cAMP-dependent protein kinase, termed C,, C,, C, and PrKX have been identified. Here we demonstrate that the human C, gene encodes six splice variants, designated C,1, C,2, C,3, C,4, C,4ab and C,4abc. The C, splice variants differ in their N-terminal ends due to differential splicing of four different forms of exon 1 designated exon 1-1, 1-2, 1-3, 1-4 and three exons designated a, b and c. All these exons are located upstream of exon 2 in the C, gene. The previously identified human C, variant has been termed C,1, and is similar to the C, isoform identified in the mouse, ox, pig and several other mammals. Human C,2, which is the homologue of bovine C,2, has no homologue in the mouse. Human C,3 and C,4 are homologous to the murine C,3 and C,2 splice variants, whereas human C,4ab and C,4abc represent novel isofoms previously not identified in any other species. At the mRNA level, the C, splice variants reveal tissue specific expression. C,1 was most abundantly expressed in the brain, with low-level expression in several other tissues. The C,3 and C,4 splice variants were uniquely expressed in human brain in contrast to C,2, which was most abundantly expressed in tissues of the immune system, with no detectable expression in brain. We suggest that the various C, splice variants when complexed with regulatory subunits may give rise to novel holoenzymes of protein kinase A that may be important for mediating specific effects of cAMP. [source]

Expanded mutational spectrum in Cohen syndrome, tissue expression, and transcript variants of COH1,

HUMAN MUTATION, Issue 2 2009
Wenke Seifert
Abstract Cohen syndrome is characterised by mental retardation, postnatal microcephaly, facial dysmorphism, pigmentary retinopathy, myopia, and intermittent neutropenia. Mutations in COH1 (VPS13B) have been found in patients with Cohen syndrome from diverse ethnic origins. We have carried out mutation analysis in twelve novel patients with Cohen syndrome from nine families. In this series, we have identified 13 different mutations in COH1, twelve of these are novel including six frameshift mutations, four nonsense mutations, two splice site mutations, and a one-codon deletion. Since different transcripts of COH1 have been reported previously, we have analysed the expression patterns of COH1 splice variants. The transcript variant NM_152564 including exon 28b showed ubiquitous expression in all examined human tissues. In contrast, human brain and retina showed differential splicing of exon 28 (NM_017890). Moreover, analysis of mouse tissues revealed ubiquitous expression of Coh1 homologous to human NM_152564 in all examined tissues but no prevalent alternative splicing. © 2008 Wiley-Liss, Inc. [source]

Genomic origin, processing and developmental expression of testicular outer dense fiber 2 (ODF2) transcripts and a novel nucleolar localization of ODF2 protein

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 11 2008
Eugene Rivkin
Abstract Outer dense fibers are a major constituent of the sperm tail and outer dense fiber 2 (ODF2) protein is one of their major components. ODF2 shares partial homology with cenexin 1 and cenexin 2, regarded as centriolar proteins. We show that ODF2 and cenexin 2 transcripts are the product of differential splicing of a single gene, designated Cenexin/ODF2 and that cenexin 1 is an incomplete clone of ODF2. ODF2 terminates in exon 20b whereas in cenexin 2 this exon is spliced out and translation terminates in exon 24. We demonstrate a transcriptional switch during rat testicular development, from somatic-type to testis-type ODF2 and cenexin transcripts during the onset of meiosis. The switch is completed when spermiogenesis is established. ODF2 immunoreactive sites were visualized in the acroplaxome, along the sperm tail and the centrosome-derived sperm head-to-tail coupling apparatus. An unexpected finding was the presence of ODF2 antigenic sites, but not cenexin antigenic sites, in the dense fibrillar component of the nucleolus of Sertoli cells, spermatogonia and primary spermatocytes. The characterization of the genomic origin, processing and developmental expression of ODF2 transcript isoforms and their protein products can help reconcile differences in the literature on the role of ODF2 and cenexin in the centrosome. Furthermore, the finding of ODF2 in the dense fibrillar component of the nucleolus suggests that this protein, in addition to its presence in sperm outer dense fibers and centrosome, highlights and adds to the nucleolar function during spermatogenesis and early embryogenesis. Mol. Reprod. Dev. 75: 1591,1606, 2008. © 2008 Wiley-Liss, Inc. [source]

Stage-dependent and alternative splicing of sGnRH messengers in rainbow trout testis during spermatogenesis

MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 1 2001
Svetlana Uzbekova
Abstract The gonadotropin releasing hormone (GnRH) has long been considered as a neuropeptide involved in the control of the reproductive cycle. However, the presence of GnRH and its receptors in various tissues, including ovary and testis, suggests a role as autocrine/paracrine factor. In the present study, we report the expression of the sGnRH-1 and sGnRH-2 genes encoding salmon GnRH in rainbow trout testis throughout testicular development and spermatogenesis. We demonstrate that both sGnRH mRNA are expressed prior of sexual differentiation. In adult, northern blot analysis indicates that sGnRH-2 transcripts are expressed in the testis at higher levels than sGnRH-1 messengers. Moreover, we observed that the expression of sGnRH-2, and not sGnRH-1, messengers was stage-dependent. sGnRH-2 mRNA expression decreases at the onset and progressively rebounds at the end of spermatogenesis. In addition, we demonstrate that a complex stage-dependent and differential splicing of the sGnRH-2 messengers occurs throughout spermatogenesis. We isolated five transcripts corresponding to sGnRH-2 messengers. Two of them may encode a novel and shortened GnRH-associated peptide containing 18 residues instead of 46. Our data provide new insight in the putative role of GnRH and GAP peptides as autocrine/paracrine factors of spermatogenesis. Mol. Reprod. Dev. 59:1,10, 2001. © 2001 Wiley-Liss, Inc. [source]

ERK-regulated differential expression of the Mitf 6a/b splicing isoforms in melanoma

PIGMENT CELL & MELANOMA RESEARCH, Issue 1 2010
Aline Primot
Summary The master regulator of the melanocyte lineage Mitf is intimately involved in development as well as melanoma, controlling cell survival, differentiation, proliferation and metastasis/migration. Consistent with its central role, Mitf expression and Mitf post-translational modifications are tightly regulated. An additional potential level of regulation is afforded by differential splicing of Mitf exon-6 leading to the generation of two isoforms that differ by the presence of six amino-acids in the Mitf (+) isoform and which have differential effects on cell cycle progression. However, whether the ratio of the two isoforms is regulated and whether their expression correlates with melanoma progression is not known. Here, we show that the differential expression of the Mitf 6a/b isoforms is dependent on the MAPKinase signalling, being linked to the activation of MEK1-ERK2, but not to N-RAS/B-RAF mutation status. In addition, quantification of Mitf 6a/b splicing forms in 86 melanoma samples revealed substantially increased levels of the Mitf (,) form in a subset of metastatic melanomas. The results suggest that differential expression of the Mitf 6a/b isoforms may represent an additional mechanism for regulating Mitf function and melanoma biology. [source]

Detection and characterization by high-performance liquid chromatography and mass spectrometry of two truncated goat ,s2 -caseins

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2006
Vincenzo Cunsolo
The identification and characterization of truncated forms of goat ,s2 -Cn variants A and E are reported. The two proteins, which have experimental Mr values of 24,183 and 24,227,Da, were detected as minor components in a goat milk sample from an autochthonous breed of southern Italy, ,Rossa Mediterranea', by reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (RP-HPLC/ESI-MS). Characterization of the amino acid sequences, performed by coupling trypsin digestion with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), RP-HPLC/ESI-MS and tandem mass spectrometry (MS/MS), demonstrated that the polypeptide chains correspond to the 1-204 sequence of mature ,s2 -Cn variant A (component with Mr of 24,183,Da) and E (component with Mr of 24,227,Da), respectively. These components seem to be the product of a differential splicing of pre-messenger RNA during the translation process of the ,s2 -Cn variants A and E. Copyright © 2006 John Wiley & Sons, Ltd. [source]