LEVELS OF COMPENSATION BETWEEN HISTONE H2A VARIANTS IN C. ELEGANS
Daniel Zamora, Diana Chu.
San Francisco State University, San Francisco, CA.
Sperm chromatin abnormalities or DNA damage can lead to male infertility. Histones, proteins that package DNA, are involved in tightening or loosening DNA for transcription. The DNA gets wrapped around a core of 4 different types of histones, one of which is H2A. Canonical H2A is replaced by different variants of H2A, each of which plays distinct roles in growth and development in Caenorhabditis elegans. One such variant, HTZ-1, is found in every cell of the developing embryo and is essential to normal development. HTAS-1, a sperm-specific histone variant, localizes with meiotic chromosomes and is found on mature sperm. In an htas-1 mutant, there is an 18% decrease in progeny. Furthermore, the deletion of another H2A variant, his-35, shows a 35% decrease in progeny. htas-1 and his-35 double mutants show complete sterility. This data shows that HTAS-1 may partially compensate for HIS-35, suggesting that histone variants may share a similar role in fertility. We will ask whether HTZ-1 can compensate for HTAS-1 by inserting HTZ-1 into the location and time where HTAS-1 is normally expressed. By expressing HTZ-1 in the htas-1;his-35 double mutant, we can quantify the progeny levels to determine the degree of rescue provided by HTZ-1 compared with HTAS-1. The results of this experiment would show whether histone H2A variants are similar enough in function to compensate for the loss of function of another variant during spermatogenesis.