Sexual differentiation in Drosophila is regulated through alternative splicing of doublesex. Female-specific splicing is activated through the activity of splicing enhancer complexes assembled on multiple repeat elements. Each of these repeats serves as a binding platform for the cooperative assembly of a heterotrimeric complex consisting of the SR proteins Tra, Tra2 and 9G8. Using quantitative kinetic analyses, we demonstrate that each component of the enhancer complex is capable of recruiting the spliceosome. Surprisingly, Tra, Tra2 and 9G8 are much stronger splicing activators than other SR protein family members and their activation potential is significantly higher than expected from their serine/arginine content. 9G8 activates splicing not only through its RS domains but also through its RNA-binding domain. The RS domains of Tra and Tra2 are required but not sufficient for efficient complex assembly. Thus, the regulated assembly of the dsx enhancer complexes leads to the generation of an extended activation domain to guarantee the ‘all or none’ splicing switch that is required during Drosophila sexual differentiation. 相似文献
Mutations in the human tau gene leading to aberrant splicing have been identified in FTDP-17, an autosomal dominant hereditary neurodegenerative disorder. Molecular mechanisms by which such mutations cause tau aberrant splicing were not understood. We characterized two mutations in exon 10 of the tau gene, N279K and Del280K. Our results revealed an exonic splicing enhancer element located in exon 10. The activity of this AG-rich splicing enhancer was altered by N279K and Del280K mutations. This exonic enhancer element interacts with human Tra2 beta protein. The interaction between Tra2 beta and the exonic splicing enhancer correlates with the activity of this enhancer element in stimulating splicing. Biochemical studies including in vitro splicing and RNA interference experiments in transfected cells support a role for Tra2 beta protein in regulating alternative splicing of human tau gene. Our results implicate the human tau gene as a target gene for the alternative splicing regulator Tra2 beta, suggesting that Tra2 beta may play a role in aberrant tau exon 10 alternative splicing and in the pathogenesis of tauopathies. 相似文献
Protein splicing is a series of enzymatic events involving intramolecular protein breakage, rejoining and intron homing, in which introns are able to promote the recombinative transposition of their own coding sequences. Eukaryotic and prokaryotic spliced proteins have conserved similar gene structure, but little amino acid identity. The genes coding for these spliced proteins contain internal in-frame introns that encode polypeptides that apparently self-excise from the resulting host protein sequences. Excision of the ‘protein intron’ is coupled with joining of the two flanking protein regions encoded by exons of the host gene. Some introns of this type encode DNA endonucleases, related to Group I RNA intron gene products, that stimulate gene conversion and self-transmission. 相似文献
The present study demonstrates that the expression of Tra2beta1 (Transformer 2-beta1) proteins, an SR (serine/arginine rich) protein, is developmentally up-regulated in a neural-specific pattern. The up-regulation is also observed in RA (retinoic acid) induced neural differentiation of P19 cells. Tra2betal proteins are located in the nuclei of P19 cells, which are consistent with its functional site as an SR protein. The over-expression of Tra2betal proteins promotes RA induced neuronal differentiation of P19 cells. In P19 cells, the splicing of FGF-2R (fibroblast growth factor receptor 2) minigene produces the BEK form, while the alternative splicing of GluR-B (glutamate receptor subunit B) minigene generates two products, the Flop and the Truncated isoforms. Tra2betal inhibits the BEK splicing, but it promotes the Flop splicing. The results therefore suggest that Tra2betal is involved in the regulation of alternative splicing processes during neural development, peculiarly the splicing of FGF-2R and GluR-B genes. Both FGF-2R and GluR-B genes are known to play important roles in neural differentiation. 相似文献
Transfer-defective mutants of the 10.4-kb Tra 2/Tra 3 region of RP1 were identified by their ability to be complemented by clones carrying all or part of this region. The respective mutations occurred in six cistrons whose order (traA, B, E, R, P, Q) and location were determined by deletion and insertion mapping. The cistrons occupy a minimum of 5.5 kb with the most distal, traA, spanning the 28.0-kb map position and traR the KpnI site at map position 24.1 kb. Each cistron is expressed independently, as Tn5 or Tn504 insertions in any one cistron do not affect the other five. The phenotypes controlled by each cistron suggest that all contribute to pilus biosynthesis/function while three (traB, R, and P) also contribute to surface exclusion. Given the occurrence of tra cistrons in the "silent" region between Tra 2 and Tra 3 we propose that the epithet "Tra 2" should be used to describe this entire region. 相似文献
The receptor for advanced glycation end products (RAGE) gene expresses two major alternative splicing isoforms, full‐length membrane‐bound RAGE (mRAGE) and secretory RAGE (esRAGE). Both isoforms play important roles in Alzheimer's disease (AD) pathogenesis, either via interaction of mRAGE with β‐amyloid peptide (Aβ) or inhibition of the mRAGE‐activated signaling pathway. In the present study, we showed that heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and Transformer2β‐1 (Tra2β‐1) were involved in the alternative splicing of mRAGE and esRAGE. Functionally, two factors had an antagonistic effect on the regulation. Glucose deprivation induced an increased ratio of mRAGE/esRAGE via up‐regulation of hnRNP A1 and down‐regulation of Tra2β‐1. Moreover, the ratios of mRAGE/esRAGE and hnRNP A1/Tra2β‐1 were increased in peripheral blood mononuclear cells from AD patients. The results provide a molecular basis for altered splicing of mRAGE and esRAGE in AD pathogenesis.