Sex-specific role of Drosophila HP1 in regulating chromatin structure and gene transcription

Drosophila heterochromatin protein 1- HP11 is believed to be involved in active transcription, transcriptional gene silencing, and the formation of heterochromatin2-7. However, little is known about the function of HP1 during development. Using a Gal4-induced RNA interference system, we show that conditional depletion of HP1 in transgenic flies results in preferential lethality in male flies. Cytological analysis of mitotic chromosomes reveals that HP1 depletion causes sex-biased chromosomal defects, including telomere fusions. The global levels of specific histone modifications, particularly the hallmarks of active chromatin, are preferentially increased in males as well. Expression analysis revealed that approximately twice as many genes are specifically regulated by HP1 in males compared to females. Furthermore, HP1-regulated genes showed greater enrichment for HP1 binding in males. Taken together, these results reveal that HP1 modulates chromosomal integrity, histone modifications, and transcription in a sex-specific manner.

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Liu LP, Ni JQ, Shi YD, Oakeley EJ, Sun FL