Hat1 acetylates histone H4 and modulates the transcriptional program in Drosophila embryogenesis

Abstract

AbstractPost-translational modifications of histone proteins play a pivotal role in DNA packaging and regulation of genome functions. Histone acetyltransferase 1 (Hat1) proteins are conserved enzymes that modify histones by acetylating lysine residues. Hat1 is implicated in chromatin assembly and DNA repair but its role in cell functions is not clearly elucidated. We report the generation and characterization of aHat1loss-of-function mutant inDrosophila.Hat1mutants are viable and fertile with a mild sub-lethal phenotype showing thatHat1is not essential in fruit flies. Lack of Hat1 results in the near complete loss of histone H4 lysine (K) 5 and K12 acetylation in embryos, indicating that Hat1 is the main acetyltransferase specific for these marks in this developmental stage. We found that Hat1 function and the presence of these acetyl marks are not required for the nuclear transport of histone H4 as histone variant His4r retained its nuclear localization both inHat1mutants and in His4r-K5R-K12R double point mutants. RNA-seq analysis of embryos indicate that inHat1mutants over 2000 genes are dysregulated and the observed transcriptional changes imply a delay in the developmental program of gene expression.