The Drosophila pipsqueak gene encodes a nuclear BTB-domain-containing protein required early in oogenesis.
Mutations at the pipsqueak locus affect early patterning in the Drosophila egg and embryo. We have cloned pipsqueak and found that it is a large and complex gene, encoding multiple transcripts and protein isoforms. One protein, PsqA, is absent in all of the mutants that we have examined. We show that PsqA is a nuclear protein present in the germ cells and somatically derived follicle cells throughout oogenesis and that it is required prior to stage one of oogenesis. PsqA contains a BTB (POZ) domain at its amino terminus; additionally, we have identified an evolutionarily conserved motif of unknown function present four times in tandem at the C terminus of the protein. PZ pipsqueak mutants produce a putative fusion protein containing the pipsqueak BTB domain fused to sequences resident on the PZ element (H. Horowitz and C. Berg, 1995 Genetics 139, 327-335). We demonstrate here that expression of this fusion protein in wild-type flies has a dominant effect, resulting in infertility and eggshell defects. These dominant phenotypes are discussed in light of current theories on the role of the BTB domain in protein-protein interactions.
Horowitz
H
H
Department of Genetics, University of Washington, Seattle, 98195-7360, USA.
Berg
C A
CA
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins; D005260:Female; D005298:Fertility / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D007301:Insect Hormones / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000502:physiology; D009866:Oogenesis / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D016211:Transforming Growth Factor alpha; D015291:Transforming Growth Factors / Q000378:metabolism
D029721:Drosophila Proteins; D007301:Insect Hormones; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D016211:Transforming Growth Factor alpha; C083730:grk protein, Drosophila; C097735:psq protein, Drosophila; D015291:Transforming Growth Factors; D004247:DNA