Temporal regulation of Drosophila salivary gland degeneration by the Broad-Complex transcription factors.
The destruction of obsolete larval tissues at the onset of insect metamorphosis is a complex process triggered by the steroid hormone ecdysone. Among the genes required for the implementation of salivary gland (SG) degeneration the reduced bristles on palpus (rbp) gene of the Broad-Complex (BR-C) locus plays a critical role. This gene encodes the BR-C Z1 transcription factor and its expression is directly regulated by ecdysone through the ecdysone receptor (EcR/Usp). The BR-C locus encodes four major protein isoforms, including BR-C Z1, Z2, Z3, and Z4. With the exceptions of mutations in BR-C Z1 all mutations affecting the other BR-C isoforms produce pupal lethality. To gain insight into the function of the different BR-C isoforms on the process of SG degeneration, we used transgenes expressing each of the four major BR-C isoform proteins. This study revealed that, depending upon the period of expression relative to the major peak of ecdysone production, BR-C Z1, Z2, and Z4 first inhibited and then stimulated the process of SG degeneration. In contrast, BR-C Z3 exerted all time points an inhibition on SG degeneration.
Kuchárová-Mahmood
Silvia
S
Institute of Experimental Endocrinology, Slovak Academy of Sciences, Vlárska 3, 83306 Bratislava, Slovakia.
Raska
Ivan
I
Mechler
Bernard M
BM
Farkas
Robert
R
D000818:Animals; D015153:Blotting, Western; D016923:Cell Death; D004330:Drosophila / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism* / Q000502:physiology*; D004440:Ecdysone / Q000378:metabolism; D007150:Immunohistochemistry; D020033:Protein Isoforms; D012469:Salivary Glands / Q000378:metabolism*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism* / Q000502:physiology*; D019076:Transgenes
C102117:Br protein, Drosophila; D029721:Drosophila Proteins; D020033:Protein Isoforms; D014157:Transcription Factors; D004440:Ecdysone