The Heterochromatin protein 1 (HP1) is involved in germline stem cells maintenance

HP1 (Heterochromatin Protein 1) is a nonhistone chromosomal protein first discovered in Drosophila melanogaster by its association with the heterochromatin and through mutations that suppressed the silencing effect of heterochromatin in position-effect variegation. Numerous studies have shown that such protein is phylogenetically highly conserved and play a role in heterochromatin formation and gene silencing in many organisms. More recently, cytogenetical and molecular studies, performed in Drosophila and in other organisms, have revealed that HP1 associates also with telomeres and multiple euchromatic sites. All these studies collectively have shown that these three different positions are related to three different functions of HP1: heterochromatin formation and gene silencing, telomeric capping and silencing, and positive control of gene expression. Since it has been observed that HP1 is highly abundant in adult ovaries and testis, we have performed studies to test if this abundance could be related to its involvement in germ stem cell (GSC) regulation. We will presents the results of our experiments showing that HP1 is involved in GSC maintainance and transposon silencing.