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Evidence that a combined activator‐repressor protein regulates Dictyostelium stalk cell differentiation.
Author(s) -
Kawata T.,
Early A.,
Williams J.
Publication year - 1996
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.1460-2075.1996.tb00671.x
Subject(s) - repressor , biology , dictyostelium , activator (genetics) , promoter , gene , dictyostelium discoideum , yy1 , dna binding protein , microbiology and biotechnology , psychological repression , genetics , transcription factor , gene expression
The ecmA gene is expressed in Dictyostelium prestalk cells and is inducible by differentiation‐inducing factor (DIF), a low‐molecular‐weight lipophilic substance. The ecmB gene is expressed in stalk cells and is under negative control by two repressor elements. Each repressor element contains two copies of the sequence TTGA in an inverted relative orientation. There are activator elements in the ecmA promoter that also contain two TTGA sequences, but in the same relative orientation. Gel retardation assays suggest that the same protein binds to the ecmB repressor and the ecmA activator. We propose that DIF induces prestalk cell differentiation by activating this protein and that the protein also binds to the promoters of stalk‐specific genes, acting as a repressor that holds cells in the prestalk state until culmination is triggered.