trachealess encodes a bHLH-PAS protein that is an inducer of tracheal cell fates in Drosophila.
The embryonic tracheal system in Drosophila develops from placodes of precursor cells on the ectoderm. A transcription factor of the basic helix-loop-helix (bHLH)-PAS family, which is expressed in the nuclei of the tracheal cells throughout development, was identified. The protein shows the highest degree of homology to the Single-minded (Sim) protein. The transcript represents the previously identified trachealess (trh) locus, essential for tracheal development. Ectopic expression of trh leads to generation of extra tracheal pits and branches and to the expression of tracheal markers by patches of ectodermal cells. The expression of trh is consistent with a biphasic mode of transcriptional regulation. Expression is first induced by exogenous cues and is subsequently autoregulated. trh is also expressed and required in the posterior spiracles and the salivary gland ducts. The role of Trachealess in the formation of several tubular tissues in the embryo suggests that it may induce a general fate of branched tubular structures of epithelial origin.
Wilk
R
R
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
Weizman
I
I
Shilo
B Z
BZ
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001426:Bacterial Proteins; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation; D003001:Cloning, Molecular; D017630:Connexins; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D004627:Embryonic Induction / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics; D006358:Hot Temperature; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014132:Trachea / Q000196:embryology* / Q000648:ultrastructure; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D001426:Bacterial Proteins; D051792:Basic Helix-Loop-Helix Proteins; D017630:Connexins; D004251:DNA Transposable Elements; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C052837:eve protein, Drosophila; C079324:shakB protein, Drosophila; C089449:sim protein, Drosophila; C099995:trh protein, Drosophila