OVO transcription factors function antagonistically in the Drosophila female germline.
OVO controls germline and epidermis differentiation in flies and mice. In the Drosophila germline, alternative OVO-B and OVO-A isoforms have a common DNA-binding domain, but different N-termini. We show that these isoforms are transcription factors with opposite regulatory activities. Using yeast one-hybrid assays, we identified a strong activation domain within a common region and a counteracting repression domain within the OVO-A-specific region. In flies, OVO-B positively regulated the ovarian tumor promoter, while OVO-A was a negative regulator of the ovarian tumor and ovo promoters. OVO-B isoforms supplied ovo(+) function in the female germline and epidermis, while OVO-A isoforms had dominant-negative activity in both tissues. Moreover, elevated expression of OVO-A resulted in maternal-effect lethality while the absence of OVO-A resulted in maternal-effect sterility. Our data indicate that tight regulation of antagonistic OVO-B and OVO-A isoforms is critical for germline formation and differentiation.
Andrews
J
J
Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, Bethesda MD, USA.
Garcia-Estefania
D
D
Delon
I
I
Lü
J
J
Mével-Ninio
M
M
Spierer
A
A
Payre
F
F
Pauli
D
D
Oliver
B
B
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029721:Drosophila Proteins; D005260:Female; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D009866:Oogenesis; D010053:Ovary / Q000254:growth & development / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018398:Homeodomain Proteins; C490318:Ovo1 protein, mouse; D020033:Protein Isoforms; D014157:Transcription Factors; C089512:ovo protein, Drosophila