DMCA
Cooperative Assembly of an hnRNP Complex Induced by a Tissue-Specific Homolog of Polypyrimidine Tract Binding Protein (2000)
BibTeX
@MISC{Chou00cooperativeassembly,
author = {Min-yuan Chou and Douglas L. Black},
title = {Cooperative Assembly of an hnRNP Complex Induced by a Tissue-Specific Homolog of Polypyrimidine Tract Binding Protein},
year = {2000}
}
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Abstract
Splicing of the c-src N1 exon in neuronal cells depends in part on an intronic cluster of RNA regulatory elements called the downstream control sequence (DCS). Using site-specific cross-linking, RNA gel shift, and DCS RNA affinity chromatography assays, we characterized the binding of several proteins to specific sites along the DCS RNA. Heterogeneous nuclear ribonucleoprotein (hnRNP) H, polypyrimidine tract binding protein (PTB), and KH-type splicing-regulatory protein (KSRP) each bind to distinct elements within this sequence. We also identified a new 60-kDa tissue-specific protein that binds to the CUCUCU splicing repressor element of the DCS RNA. This protein was purified, partially sequenced, and cloned. The new protein (neurally enriched homolog of PTB [nPTB]) is highly homologous to PTB. Unlike PTB, nPTB is enriched in the brain and in some neural cell lines. Although similar in sequence, nPTB and PTB show significant differences in their properties. nPTB binds more stably to the DCS RNA than PTB does but is a weaker repressor of splicing in vitro. nPTB also greatly enhances the binding of two other proteins, hnRNP H and KSRP, to the DCS RNA. These experiments identify specific cooperative interactions between the proteins that assemble onto an intricate splicing-regulatory sequence and show how this hnRNP assembly is altered in different cell types by incorporating different but highly related proteins. Alternative splicing is a common mechanism for regulating
Keyphrases
dc rna polypyrimidine tract binding protein cooperative assembly tissue-specific homolog hnrnp complex induced significant difference neural cell line different cell type downstream control sequence hnrnp assembly intricate splicing-regulatory sequence cucucu splicing repressor element new 60-kda tissue-specific protein rna regulatory element rna gel shift site-specific cross-linking c-src n1 exon several protein distinct element unlike ptb neuronal cell new protein common mechanism alternative splicing specific cooperative interaction heterogeneous nuclear ribonucleoprotein kh-type splicing-regulatory protein related protein dc rna affinity chromatography assay intronic cluster polypyrimidine tract
