dTAF10- and dTAF10b-Containing Complexes Are Required for Ecdysone-Driven Larval-Pupal Morphogenesis in Drosophila melanogaster

Páhi, Zoltán Gábor and Kiss, Zsuzsanna and Komonyi, Orbán and Borsos, Barbara and Tora, László and Boros, Imre Miklós and Pankotai, Tibor (2015) dTAF10- and dTAF10b-Containing Complexes Are Required for Ecdysone-Driven Larval-Pupal Morphogenesis in Drosophila melanogaster. PLOS ONE. pp. 1-18. ISSN 1932-6203

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Abstract

In eukaryotes the TFIID complex is required for preinitiation complex assembly which posi- tions RNA polymerase II around transcription start sites. On the other hand, histone acetyl- transferase complexes including SAGA and ATAC, modulate transcription at several steps through modification of specific core histone residues. In this study we investigated the func- tion of Drosophila melanogaster proteins TAF10 and TAF10b, which are subunits of dTFIID and dSAGA, respectively. We generated a mutation which eliminated the production of both Drosophila TAF10 orthologues. The simultaneous deletion of both d Taf10 genes impaired the recruitment of the dTFIID subunit dTAF5 to polytene chromosomes, while binding of other TFIID subunits, dTAF1 and RNAPII was not affected. The lack of both dTAF10 pro- teins resulted in failures in the larval-pupal transition during metamorphosis and in transcrip- tional reprogramming at this developmental stage. Surprisingly, unlike dSAGA mutations, dATAC subunit mutations resulted in very similar changes in the steady state mRNA levels of approximately 5000 genes as did ablation of both d Taf10 genes, indicating that dTAF10- and/or dTAF10b-containing complexes and dATAC affect similar pathways. Importantly, the phenotype resulting from d Taf10+ d Taf10b mutation could be rescued by ectopically added ecdysone, suggesting that dTAF10- and/or dTAF10b-containing complexes are involved in the expression of ecdysone biosynthetic genes. Indeed, in d Taf10+ d Taf10b mutants, cytochrome genes, which regulate ecdysone synthesis in the ring gland, were underrepresented. Therefore our data support the idea that the presence of dTAF10 pro- teins in dTFIID and/or dSAGA is required only at specific developmental steps. We propose that distinct forms of dTFIID and/or dSAGA exist during Drosophila metamorphosis, wherein different TAF compositions serve to target RNAPII at different developmental stages and tissues.

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