The Myst domain acetyltransferase Chameau is required for JNK signalling and Pannier functions during thorax morphogenesis. B. Miotto , T. SAGNIER , M.C. MARIOL , A.. GRIENENBERGER , Y. GRABA , J. PRADEL. LGPD-IBDM, CNRS, Marseilles, France.

   chameau (chm) encodes for an acetyltransferase of the MYST family already shown to have a role in epigenetic mechanisms of transcriptional control. Here we report about the developmental function of chm during thorax morphogenesis, and its requirement for normal activities of the JNK signaling pathway and of the GATA factor Pannier (Pnr). Animals deficient for chm die as pharate adults with gross alteration in thoracic closure and scutellar bristle segregation. Preferencially express in the peripodial membrane, Chm acts downstream of the Hemipterous kinase and controls the transcription of puckered, a target gene of the JNK pathway. Consistently, the thoracic cleft phenotype of chm is enhanced by any mutation affecting the pathway. chm genetically interacts also with pnr in the expression of thoracic cleft and scutellar bristle duplication phenotypes. Epistasis experiments showed that chm, as pnr, acts upstream of the achaete-scute proneural gene in the process of scutellar bristle segregation. These data will be discussed considering Pnr and Jun as candidate substrates for acetylation by Chm.