E2F7, a novel E2F featuring DP-independent repression of a subset of E2F-regulated genes

Abstract

The E2F family of transcription factors play an essential role in the regulation of cell cycle progression. In a screen for E2F-regulated genes we identi®ed a novel E2F family member, E2F7. Like the recently identi®ed E2F-like proteins of Arabidopsis, E2F7 has two DNA binding domains and binds to the E2F DNA binding consensus site independently of DP co-factors. Consistent with being an E2F target gene, we found that the expression of E2F7 is cell cycle regulated. Ectopic expression of E2F7 results in suppression of E2F target genes and accumulation of cells in G 1 . Furthermore, E2F7 associates with E2F-regulated promoters in vivo, and this association increases in S phase. Interestingly, however, E2F7 binds only a subset of E2F-dependent promoters in vivo, and in agreement with this, inhibition of E2F7 expression results in speci®c derepression of these promoters. Taken together, these data demonstrate that E2F7 is a unique repressor of a subset of E2F target genes whose products are required for cell cycle progression.

Retinoblastoma family genes

“…Consistent with these structural features, this subgroup of E2Fs functions mainly as repressors of E2F target gene expression, and they translocate into the nucleus when in complex with the Rb family of proteins during the G0/G1 phases of the cell cycle (Muller et al, 1997;Verona et al, 1997). E2Fs 6-8, representing the remaining two subgroups, also function as transcriptional repressors (Trimarchi et al, 1998(Trimarchi et al, , 2001de Bruin et al, 2003a;Di Stefano et al, 2003;Attwooll et al, 2004b;Maiti et al, 2005). However, in contrast to E2Fs 1-5, these E2F proteins do not have the Rb-binding sequence at the C-terminus, and therefore their function and regulation are independent of the Rb family of proteins.…”

Visualization of Nuclear Localization of Transcription Factors with Cyan and Green Fluorescent Proteins in the Red Alga Porphyra yezoensis

“…Moreover, optimization the codon usage of the coding sequence of sGFP (S65T) In this study, we cloned full-length cDNAs encoding transcription factors PyDEL1, PyElf1 and PyMBF1. PyDEL1 is a homologue of DEL/E2F7 protein, which localizes specifically in the nucleus and acts as a transcription repressor in plants and animals (Kosugi and Ohashi 2002;Vandepoele et al 2002;Di Stefano et al 2003). AtDEL1, which is a homologue of DEL/E2F7 from A. thaliana, is an important inhibitor of the endocycle (DNA replication without mitosis), preserving the mitotic state of proliferating cells by suppressing transcription of genes required for cells to enter the 13 DNA endoreduplication cycle (Vlieghe et al 2005).…”

Life and death decisions by the E2F transcription factors

“…The silencing function of E2F6 appears to be due to its ability to associate with members of the Polycomb group of transcriptional repressors [1]. E2F7 and E2F8 also behave as repressors, and may function in a manner analogous to E2F6 [3], yet the biological functions of these proteins are just beginning to be understood. Interestingly, E2F7 and E2F8 are unique among E2Fs in their ability to bind DNA in the absence of interaction with a DP subunit, the normal dimerization partner of E2Fs.…”