期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1996
卷号：93
期号：15
页码：7594-7599
DOI：10.1073/pnas.93.15.7594
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：E2F is a heterodimeric transcription factor that regulates the expression of genes at the G1/S boundary and is composed of two related but distinct families of proteins, E2F and DP. E2F/DP heterodimers form complexes with the retinoblastoma (Rb) protein, the Rb-related proteins p107 and p130, and cyclins/cdks in a cell cycle-dependent fashion in vivo. E2F is encoded by at least five closely related genes, E2F-1 through -5. Here we report studies of DP-2, the second member of the DP family of genes. Our results indicate that (i) DP-2 encodes at least five distinct mRNAs, (ii) a site of alternative splicing occurs within the 5' untranslated region of DP-2 mRNA, (iii) at least three DP-2-related proteins (of 55, 48, and 43 kDa) are expressed in vivo, (iv) each of these proteins is phosphorylated, and (v) one DP-2 protein (43 kDa) carries a truncated amino terminus. Our data also strongly suggest that the 55-kDa DP-2-related protein is a novel DP-2 isoform that results from alternative splicing. Thus, we conclude that DP-2 encodes a set of structurally, and perhaps functionally, distinct proteins in vivo.
