Date of Award
PhD Molecular Bioscience
Angela V. Klaus, Ph.D ; Tin-Chun Chu, Ph.D
Jane L. Ko, Ph.D
Carolyn Bentivegna, Ph.D
Brian Nichols, Ph.D
Valeria Schawaroch, Ph.D
spermatogenesis, Tpl94D, transition proteins, RNA-Seq, gene expression, DEG
Spermatogenesis is the process by which mature functional spermatozoa are formed, and is initiated in the stem cell niche of the testes. During the post-meiotic stage of spermatogenesis, spermiogenesis, transition proteins facilitate the transformation of chromatin from a histone-based nucleosome structure to a protamine-based nucleosome structure. This study is aimed at analyzing genomic, transcript, and protein sequences of transition proteins in 13 sequenced Drosophila species. The Drosophila melanogaster spermatid specific transition protein-like protein (Tpl94D) was used as the reference sequence in this study. An extensive bioinformatics approach was employed in establishing the Tpl94D orthologs. We identified Tpl94D orthologs in the melanogaster subgenus (D. simulans, D. sechellia, D. erecta, and D. yakuba), D. ananassae, D. miranda, and D. pseudoobscura. In contrast, no Tpl94D orthologs were identified in D. persmilis, D. willistoni, or the Drosophila subgenus (D. mojavensis, D. virilis, and D. grimshawi) due to their evolutionary distance from D. melanogaster. Differential gene expression analysis of the testes versus the ovaries showed high expression of Tpl94D orthologs in the testes for in D. melanogaster, D. simulans, D. yakuba, D. ananassae, D. miranda, and D. pseudoobscura. Further RNA-Seq analysis using the NIH Isoform Two-Step Analysis revealed higher testes expression for D. melanogaster Tpl94D isoform A (164 amino acids) than D. melanogaster Tpl94D isoform B (163 amino acids). We confirmed the conservation of a HMG box/DNA binding domain among transition protein (Tpl94D ) orthologs and Drosophila male specific transcript protamine-like protein (MST35Ba/MST35Bb) orthologs. Overall, this study represents the first large-scale, single-genus invertebrate dataset for transition proteins and provides the basis for a fine-grained analysis of their evolution.
Alvi, Zain A., "A Bioinformatics Methodology for the Annotation and Analysis of Sperm Chromatin Remodeling Proteins in Sequenced Drosophila Species" (2016). Seton Hall University Dissertations and Theses (ETDs). 2253.