The Cotton-Top Tamarin (Saguinus oedipus) Has Five β-Microseminoprotein Genes, Two of Which Are Pseudogenes

Abstract

beta-Microseminoprotein (MSP) is one of the most abundant proteins in human seminal plasma and is secreted from the prostate gland. Its evolution can be traced from primates down to nonvertebrate species such as amphioxus, despite substantial differences in the primary structure. Most mammals are known to have one single MSP gene, but we have previously shown that the cotton-top tamarin and the common marmoset-two New World monkeys-carry several MSP genes. In this study we continue our characterization of MSP genes in the cotton-top tamarin by presenting the full nucleotide sequence of the three previously identified genes, mspA, mspE, and mspJ. A promoter analysis using the luciferase reporter showed that mspE is as transcriptionally active as the single human MSP gene, whereas mspA and mspJ display no activity with this assay. Two novel MSP genes were also identified, mspB and mspH, both of which are pseudogenes. MspB has a frameshift mutation in the third exon resulting in a new C-terminus and premature stop of translation. MspH has the features of a processed pseudogene, originating from a transcript of mspE. It is integrated into the genome together with another processed pseudogene originating from a transcript of the nucleoporin gene NUP88. The MSP genes described in this study probably arose by phylogenetically rather late duplication or retrotransposition, suggesting that they are confined to a limited number of New World monkeys.

Rapidly evolving marmoset MSMB genes are differently expressed in the male genital tract

“…We have previously shown by Southern blotting that the common marmoset and the cotton-top tamarin have the same, or almost the same, number of MSMB s [ 14 ]. This is now confirmed by the demonstration of 5 MSMB s in the common marmoset that are orthologous with the 5 MSMB s in the cotton-top tamarin [ 15 ]. In addition, we identified a unique duplication in the marmoset MSMB1 , which has created a new potential transcription initiation site around 2.7 kb upstream of the "normal" start site.…”

“…Whether this new site is used for initiation of MSMB1 transcription or should be considered as a truncated pseudogene remains to be seen. In earlier studies on the cotton top tamarin it was not possible to determine whether the MSMB s, excluding the processed pseudogene MSMB5 , are situated at a single genetic locus, but from the location of homologous regions in two of the genes it was speculated that there probably is an MSMB located around 20 kb downstream of MSMB3 [ 15 ]. In this study on the common marmoset it was found that there is indeed a gene located 20 kb downstream of MSMB3 , but also another gene located 32 kb upstream.…”

“…the closely related cotton top tamarin ( Saguinus oedipus ) and common marmoset ( Callithrix jacchus ) of the primitive Callithricidea family, carry several MSMB in their genomes, something that is in contrast to most other vertebrate species, which carry a single MSMB [ 14 ]. More recently, we cloned and sequenced 5 MSMB from a cotton-top tamarin genomic library [ 15 ]. We concluded that 2 of them were pseudogenes, as one of them, MSMB4 , had a deletion that shifted the reading frame and lead to premature termination, and the other, MSMB5 , had the features of a processed pseudogene.…”

Egg-Laying in the Cuttlefish Sepia officinalis

“…It is only described in other vertebrates [40][41][42][43][44] and in the basal chordate amphioxus [45]. It is a highly variable 91-amino-acid protein, with 10 spatially conserved cysteine residues than can potentially form five intramolecular disulfide bonds, giving resistance to proteolytic cleavage to prolong its activity on the egg surface.…”

Extreme Aggression in Male Squid Induced by a β-MSP-like Pheromone

“…The purified egg capsule protein has highest overall sequence identity with b-microseminoproteins (b-MSPs), which were originally discovered in human seminal plasma and prostatic fluids [15] and only described in other vertebrates [16][17][18][19][20] and the basal chordate amphioxus [21]. Although highly variable (only 45% of residues are conserved between human and rat b-MSP [22]), chordate b-MSPs are typically 88-95 amino acids in length, possess ten spatially conserved cysteine residues, are resistant to proteolytic cleavage, and are secreted, yet they do not appear to be glycosylated [21,23,24].…”