A critical role of teashirt for patterning the ventral epidermis is masked by ectopic expression of tiptop, a paralog of teashirt in Drosophila.
The teashirt gene encodes a protein with three widely spaced zinc finger motifs that is crucial for specifying trunk identity in Drosophila embryos. Here, we describe a gene called tiptop, which encodes a protein highly similar to Teashirt. We have analyzed the expression patterns and functions of these two genes in the trunk of the embryo. Initially, teashirt and tiptop expressions are detected in distinct domains; teashirt in the trunk and tiptop in parts of the head and tail. In different mutant situations, we show that, in the trunk and head, they repress each other's expression. Unlike teashirt, we found that deletion of tiptop is homozygous viable and fertile. However, embryos lacking both gene activities display a more severe trunk phenotype than teashirt mutant embryos alone. Ectopic expression of either gene produces an almost identical phenotype, indicating that Teashirt and Tiptop have, on the whole, common activities. We conclude that Teashirt and Tiptop repress each other's expression and that Teashirt has a crucial role for trunk patterning that is in part masked by ectopic expression of Tiptop.
Laugier
Edith
E
IBDM, LGPD, UMR 6545, CNRS/INSERM/Université de la Méditerranée, Campus de Luniny, Case 907, Marseille, France.
Yang
Zhaohai
Z
Fasano
Laurent
L
Kerridge
Stephen
S
Vola
Christine
C
D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D004330:Drosophila / Q000196:embryology* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000502:physiology; D004817:Epidermis / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D016335:Zinc Fingers
D029721:Drosophila Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C496672:tio protein, Drosophila; C066830:tsh protein, Drosophila