E2F-4 and E2F-5, two members of the E2F family, are expressed in the early phases of the cell cycle.
Proceedings of the National Academy of Sciences, 1995•National Acad Sciences
The E2F transcription factors play a role in regulating the expression of genes required for
cell proliferation. Their activity appears to be regulated by association with the
retinoblastoma protein (pRb) and the pRb-related proteins p107 and p130. In vivo, pRb is
found in complex with a subset of E2F components--namely, E2F-1, E2F-2, and E2F-3. Here
we describe the characterization of cDNAs encoding two unusual E2Fs, E2F-4 and E2F-5,
each identified by the ability of their gene product to interact with p130 in a yeast two-hybrid …
cell proliferation. Their activity appears to be regulated by association with the
retinoblastoma protein (pRb) and the pRb-related proteins p107 and p130. In vivo, pRb is
found in complex with a subset of E2F components--namely, E2F-1, E2F-2, and E2F-3. Here
we describe the characterization of cDNAs encoding two unusual E2Fs, E2F-4 and E2F-5,
each identified by the ability of their gene product to interact with p130 in a yeast two-hybrid …
The E2F transcription factors play a role in regulating the expression of genes required for cell proliferation. Their activity appears to be regulated by association with the retinoblastoma protein (pRb) and the pRb-related proteins p107 and p130. In vivo, pRb is found in complex with a subset of E2F components--namely, E2F-1, E2F-2, and E2F-3. Here we describe the characterization of cDNAs encoding two unusual E2Fs, E2F-4 and E2F-5, each identified by the ability of their gene product to interact with p130 in a yeast two-hybrid system. E2F-4 and -5 share common sequences with E2F-1, E2F-2, and E2F-3 and, like these other E2Fs, the ability to heterodimerize with DP-1, thereby acquiring the ability to bind an E2F DNA recognition sequence with high affinity. However, in contrast to E2F-1, E2F-4 and E2F-5 fail to bind pRb in a two-hybrid assay. Moreover, they show a unique pattern of expression in synchronized human keratinocytes: E2F-4 and E2F-5 mRNA expression is maximal in mid-G1 phase before E2F-1 expression is detectable. These findings suggest that E2F-4 and E2F-5 may contribute to the regulation of early G1 events including the G0/G1 transition.
National Acad Sciences