Distinct expression patterns and transforming properties of multiple isoforms of Ost, an exchange factor for RhoA and Cdc42

被引：21

作者：

Lorenzi, MV ^{[1
]}

Castagnino, P ^{[1
]}

Chen, Q ^{[1
]}

Hori, Y ^{[1
]}

Miki, T ^{[1
]}

机构：

[1] NCI, Cellular & Mol Biol Lab, Bethesda, MD 20892 USA

来源：

ONCOGENE | 1999年 / 18卷 / 33期

关键词：

expression cloning; cell cycle; alternative splicing; embryogenesis;

D O I：

10.1038/sj.onc.1202851

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

A search for transforming genes expressed in brain led to the identification of a no, el isoform of Ost. an exchange factor for RhoA and Cdc42, In addition to the Dbl-homology (DH) and pleckstrin-homology (PH) domains identified in the original Ost, this isoform contained a SH3 domain and a novel) HIV-Tat related (TR) domain. The presence or absence of these domains in Ost defined multiple isoforms of the protein. RT-PCR and in situ hybridization analysis revealed that these isoforms were generated by tissue-specific and developmentally restricted alternative splicing events. Whereas deletion of the N-terminus activated the transforming properties of Ost, the presence of the SH3 domain reduced the transforming activity of the protein. This inhibition mas relieved by the presence of a TR domain, which contained a potential SH3 ligand sequence. The transforming activity of all Ost isoforms was inhibited by dominant negative forms of the Rho family proteins. Expression of Ost isoforms potently induced the formation of actin stress fibers and filopodia as well as JNK activity and AP1- and SRF-regulated transcriptional pathways. Ost transfectants also displayed elevated levels of cyclins A and D1, suggesting that the de-regulation of these cyclins is linked to Oat-mediated transformation.

引用

页码：4742 / 4755

页数：14

共 35 条

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