The molecular evolution of acrosin in placental mammals

Abstract

Acrosin is thought to fulfill several different roles in fertilization including that of a serine protease and in secondary zona pellucida (ZP) binding. However, acrosin's importance as a fertilization protein has been questioned. Especially since it was discovered that acrosin knockout mice are fertile. In this study, we explored the sites involved in serine protease activity and secondary binding. We also assessed conservation in functional sites across species and examined whether amino acid changes present in the human population have the potential to affect fertility. In addition, since many mammalian reproduction proteins have been found to evolve rapidly, we tested for positive selection. Sequences from 43 mammals from all 19 placental orders, which included a total of 828 nucleotides from acrosin exons 2, 3, 4, and a portion of exon 5, were obtained. We found that all sites of the serine catalytic triad as well as three other sites linked to catalytic activity were completely conserved. Five of six sites proposed to play a role in secondary binding were 100% conserved as basic residues. These results support an evolutionary conserved role for acrosin as a serine protease and secondary binding protein across placental mammals. We found statistically significant support for positive selection within acrosin, but no single amino acid site reached the significance level of P > 0.95 for inclusion within the category omega > 1. Based upon two amino acid mutation scoring systems, three out of seven human residue changing single nucleotide polymorphisms (SNPs) were found to be potentially protein-altering mutations.

Molecular phylogeny and evolution of the Perissodactyla

“…The phylogenetic tree obtained from the combined analysis strongly supports the taxonomic status of the suborders Ceratomorpha and Hippomorpha, and of all three perissodactyl families (Rhinocerotidae, Tapiridae, and Equidae), as initially proposed by morphological studies (Prothero et al ., 1986; Prothero & Schoch, 1989) and later confirmed by nuclear (Murphy et al ., 2001; Amrine‐Madsen et al ., 2003; Raterman & Springer, 2008) and mitochondrial genetic data (Norman & Ashley, 2000; Agnarsson & May‐Collado, 2008; Arnason et al ., 2008).…”

“…Traditionally, the Perissodactyla have been divided in two suborders: Hippomorpha containing the family Equidae, and Ceratomorpha comprising the modern families Tapiridae and Rhinocerotidae (Radinsky, 1966; Prothero & Schoch, 1989). This classification was initially based on dental and osteological morphology, and soft anatomy (Prothero, Manning & Hanson, 1986; Prothero & Schoch, 1989), finding later support in molecular (Norman & Ashley, 2000; Murphy et al ., 2001; Amrine‐Madsen et al ., 2003; Agnarsson & May‐Collado, 2008; Arnason et al ., 2008; Raterman & Springer, 2008) and cytogenetic (Trifonov et al ., 2008) studies, with a few exceptions (Flint, Ryder & Clegg, 1990; Henry, Lance & Conlon, 1993; Madsen et al ., 2002).…”

Testing diversification models of endemic Philippine forest mice (Apomys) with nuclear phylogenies across elevational gradients reveals repeated colonization of isolated mountain ranges

“…Good et al ., ; Rowe et al ., ). Acrosin was chosen because it is a sperm‐expressed protease that may be under species‐specific selection (Good et al ., ; Raterman & Springer, ) and therefore might reflect biological species boundaries better than neutrally evolving genes. PCR reactions contained 21 μL of Platinum Blue PCR Supermix (Invitrogen, Carlsbad, CA, USA), 10 μ m forward and reverse primers, 25 μ m MgCl 2 and 25 ng template DNA.…”

Identification of the Second Form of Acrosin in Turkey Spermatozoa

“…2010); acrosin ( Talpa europaea ) accession no. (Talpa Acr); acrosin ( Tragelaphus angasii , Raterman and Springer 2008; Tragelaphus Acr); acrosin precursor ( Canis familiaris ), accession no. (Canis Acr).…”