Drosophila homologs of transcriptional mediator complex subunits are required for adult cell and segment identity specification.
The origins of specificity in gene expression are a central concern in understanding developmental control. Mediator protein complexes regulate transcriptional initiation, acting as modular adaptors linking specific transcription factors to core RNA polymerase II. Here, we identified the Drosophila homologs of 23 human mediator genes and mutations of two, dTRAP240 and of dTRAP80 (the putative fly homolog of yeast SRB4). Clonal analysis indicates a general role for dTRAP80 necessary for cell viability. The dTRAP240 gene is also essential, but cells lacking its function are viable and proliferate normally. Clones reveal localized developmental activities including a sex comb cell identity function. This contrasts with the ubiquitous nuclear accumulation of dTRAP240 protein in imaginal discs. Synergistic genetic interactions support shared developmental cell and segment identity functions of dTRAP240 and dTRAP80, potentially within a common complex. Further, they identify the homeotic Sex combs reduced product, required for the same cell/tissue identities, as a functional partner of these mediator proteins.
Boube
M
M
Centre de Biologie du Développement-CNRS, 31062 Toulouse CEDEX 04, France.
Faucher
C
C
Joulia
L
L
Cribbs
D L
DL
Bourbon
H M
HM
D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D003001:Cloning, Molecular; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D005801:Genes, Homeobox; D017344:Genes, Insect; D006801:Humans; D019476:Insect Proteins; D008969:Molecular Sequence Data; D012319:RNA Polymerase II / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D029721:Drosophila Proteins; D019476:Insect Proteins; C059627:Scr protein, Drosophila; D014157:Transcription Factors; D012319:RNA Polymerase II