Premium
Functional antagonism between members of the myb family: B‐myb inhibits v‐myb‐induced gene activation.
Author(s) -
Foos G.,
Grimm S.,
Klempnauer K.H.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05564.x
Subject(s) - myb , biology , genetics , gene , microbiology and biotechnology , gene expression
The oncogene v‐myb and its cellular progenitor c‐myb encode nuclear, DNA binding phosphoproteins that control the expression of certain target genes in immature hematopoietic cells. Here, we report the isolation of a myb‐related chicken gene, chicken B‐myb. We show that expression of B‐myb, unlike that of c‐myb, is not restricted to hematopoietic cells, suggesting that B‐myb functions in a broader spectrum of cell types than c‐myb. We have identified the authentic chicken B‐myb protein as a nuclear protein of approximately 110 kDa. We show that the B‐myb protein specifically recognizes v‐myb binding sites in vitro and that binding is mediated by an N‐terminally located DNA binding domain. Although B‐myb protein recognizes myb binding sites, B‐myb fails to transactivate several myb‐responsive gene constructs as well as the endogenous myb‐responsive gene mim‐1. Instead, we find that B‐myb represses v‐myb‐ and c‐myb‐mediated activation of the mim‐1 gene, most likely by competing with other myb proteins for binding sites. Our results raise the possibility that B‐myb is an inhibitory member of the myb family.