Protamine-like Proteins in 12 Sequenced Species of Drosophila

Genomic and expression analysis of transition proteins inDrosophila

“…4,5 Amino acid analysis for Tpl 94D and conserved region Several studies have focused on the number and the percentages of amino acids present in TPs [39][40][41] and SNBPs. 3,13,42,43 The Tpl 94D orthologs found in the 12 Drosophila species analyzed in the current work are less rich in basic amino acids when compared to their mammalian counterparts, but they still share specific characteristics that classify them as TPs. 6,13,27 For example, Tpl 94D and mammalian TPs cause a disruption of the histone nucleosome organization to facilitate the sperm chromatin transition to a protamine bound structure.…”

“…Previous studies have characterized transition proteins, histone H1 linker-like, protamine-like, and true protamines based on distinct percentage of basic amino acids (lysine and arginine) and other specific amino acids like cysteine, tyrosine, and serine. 4,13,15,17,27 Table 4 indicates species that are within the melanogaster species subgroup (Dsim GD20990-Tpl 94D , Dsec GM26474-Tpl 94D , Dyak GE10340-Tpl 94D , and Dere GG11172-Tpl 94D ) have essentially the same number of amino acid residues as compared to the control Tpl 94D found in D. melanogaster. In contrast, Drosophila species found outside the melanogaster species subgroup have greater variance in the number of amino acid residues (79 and 101 amino acids for Dana GF19889-Tpl 94D and Dpse GA22645-Tpl 94D respectively).…”

“…2,[4][5][6] Histone H1 linker-like proteins, true protamines and protamine-like proteins appear to have evolved from histone H1 linker and are collectively referred as the "sperm nuclear basic proteins" (SNBPs). 7,8 True protamines are present in the sperm nuclei of higher vertebrates such as mice and humans, [9][10][11] while protamine-like proteins are found in some vertebrates, 12 but are predominantly found in invertebrate species such as fruit flies, 4,6,13 Atlantic surf clam, [13][14][15] and stalked tunicate. 16 Adult male Drosophila fruit flies and mammals have a similar process of spermatogenesis.…”

“…3 The D. melanogaster protamine-like proteins are male specific transcripts MST35Ba and MST35Bb. 1,2,4,13,23 The purpose of MST35Ba and MST35Bb appears to be to serve as the protector of the compacted DNA in the sperm nucleus against detrimental environmental factors such as X-rays. 6 Furthermore, deletion of MST35Ba and MST35Bb does not significantly affect chromatin condensation or fertility as it does in mammals when true protamines are deleted.…”

“…D. simulans, D. sechellia, D. yakuba, D. erecta, D. erecta, D. ananassae, D. persimilis, D. pseudoobcura, D. willistoni, D. virilis, and D. grimshawi). 13 The current study focuses on an analysis of transition proteins (TPs) in the same 12 species analyzed in our previous work. Here, we include differential gene expression analysis using available next generation sequencing (NGS) RNA-Seq transcriptome data in addition to the genomic analysis.…”