Putative sperm chromatin condensing proteins and their respective conserved domains in 12 sequenced species of Drosophila. Zain A. Alvi, Tin-Chun Chu, Angela V. Klaus. Department of Biological Sciences, Seton Hall University, South Orange, NJ.

   Our current research is aimed at identifying and analyzing proteins that are involved in sperm chromatin condensation in the original 12 sequenced Drosophila fly species. The process of nuclear transformation occurs due to the interaction of three sperm basic proteins (SNBPs), transition protein (TPL94D in Drosophila melanogaster), and CTCF (chromatin insulating and DNA - zinc finger binding protein). The SNBPs can be divided into histone group (Histone H1 linker like and involved in chromatin condensation in Drosophila melanogaster); protamine-like proteins (DNA binding and present in Drosophila melanogaster); and true protamines (not found in Drosophila). Using the reference sequences for Drosophila melanogaster SNBPs (Mst35Ba, Mst35Bb, and Mst77F), we previously identified the putative sequences for the SNBP proteins in D. simulans, D. sechellia, D. yakuba, D. erecta, D. anannassae, D. mojavensis, D. virilis, D. willistoni, D. grimshawi, D. pseudoobscura, and D. persimilis. Our current work suggests that Mst77F and TPL94D are conserved in the melanogaster species subgroup, but not conserved in the rest of the subgenus Sophophora or in subgenus Drosophila, whereas Mst35Ba, Mst35Bb, CTCF, are conserved among the original 12 sequenced species of Drosophila flies. Mst35Ba, Mst35Bb, TPL94D, CTCF, and Mst77F all have a putative conserved DNA binding domain. Additionally, Mst77F appears to have a conserved protein-protein interaction domain. We are also analyzing chromatin condensation patterns during nuclear transformation in Drosophila sperm nuclei. Our hypothesis is that the type of SNBPs present in the sperm nucleus will affect the pattern of chromatin condensation, which in turn will affect the species-specific shape of the sperm nucleus.