Y353/B: a candidate multiple-copy spermiogenesis gene on the mouse Y chromosome

Abstract

There is evidence from Y Chromosome (Chr) deletion mapping that there is a gene on the long arm of the mouse Y Chr that is needed for the normal development of the sperm head. Since mice with partial Y long arm deletions show incomplete penetrance of the sperm head defect, whereas mice with no Y long arm show complete penetrance, it has been suggested that the 'spermiogenesis' gene may be present in multiple copies. A Y-specific genomic DNA sequence (Y353/B) has previously been described that is present in multiple copies on the long arm of the mouse Y and identifies testis-specific transcripts. We have suggested that Y353/B could be the proposed multiple copy 'spermiogenesis' gene. In support of this suggestion, we show here that mice with a partial Y long arm deletion associated with a 3.5-fold increase in the frequency of abnormal sperm heads have a marked reduction in genomic Y353/B copies and a corresponding reduction in Y353/B-related transcripts. Thus, the incompletely penetrant phenotype correlates with a reduction in Y353/B-related transcription. Furthermore, by in situ hybridization with a Y353/B riboprobe to testis sections, we show that the Y353/B-related transcripts are confined to the round spermatid stage of spermiogenesis, just prior to the shaping of the sperm head. The transcripts sediment with the fraction of cytoplasmic RNA in adult testis that is loaded on polysomes, suggesting that the transcripts are actively translated.

Spermatogenesis and sex chromosome gene content: An evolutionary perspective

“…Significantly, in these fertile Yq-deleted mice, the XY upregulation is associated with an excess of females in the offspring of affected males (Conway et al, 1994). This closes the last link in the chain, demonstrating that selfish elements are present but cryptic within the mouse genome, and that suppression of their expression is necessary to maintain a normal sex ratio.…”

“…Further work in our own laboratory (in conjunction with Paul Burgoyne's group at NIMR and Kate Loveland's group in Melbourne) on a series of mutant mouse models with deletions on the long arm of the Y chromosome (Burgoyne, Mahadevaiah, Sutcliffe, & Palmer, 1992;Conway et al, 1994;Toure et al, 2004a) shows that X and Y-linked spermatid-expressed genes are upregulated in the testes of the affected males (Ellis et al, 2005). Mice bearing large deletions are infertile, however those with smaller deletions retain fertility.…”

“…This leads to an intragenomic conflict or 'arms race' between the two, whereby large multi-copy gene families become amplified on both the X and Y chromosomes (Hurst & Pomiankowski, 1991;Partridge & Hurst, 1998). These amplified families have been observed directly in human, chimpanzee, mouse and fruit fly via sequencing projects (Nishioka & Lamothe, 1986;Eicher, Hutchison, Phipis, Tucker, & Lee, 1989;Balakireva, Shevelyov, Nurminsky, Livak, & Gvozdev, 1992;Prado, Lee, Zahed, Vekemans, & Nishioka, 1992;Conway et al, 1994;Adams et al, 2000;Kuroda-Kawaguchi et al, 2001;Rozen et al, 2003;Skaletsky et al, 2003;Toure et al, 2004b), and can be inferred in many other species by reference to the repetitive nature of Y chromosomal DNA. The arguments for repeat family accumulation apply in particular to the Y chromosome, which is non-pairing in every generation, while the X is only unpaired 1/3 of the time.…”

Partial deletion of the Y chromosome removes the effect of paternal genome imprinting on periovum sensitivity to hyaluronidase in mice

“…Phenotypically, the Y-del mutation used in this work is similar to the Y-del mutation described by Conway et al (1994). The latter has a deletion on the long arm of the Y chromosome where the Y 353/B multiple-copy gene is situated, necessary for the normal development of the sperm head.…”

Sperm Select Penetration Test Reveals Differences in Sperm Quality in Strains with Different Y Chromosome Genotype in Mice

“…However, in the BIO.BR-Yde' mutant strain, a large deletion in the long arm of the Y chromosome, which caused a deterioration of sperm morphology and capacity of in vitro fertilization, was correlated with a significant deterioration both of hyaluronate penetration and sperm membrane integrity. In the long arm of the mouse Y chromosome there is a "spermiogenesis" gene, present in multiple copies that is important for the development of normal sperm phenotype [ 2 ] . A large deletion in that arm could have affected various aspects of sperm morphology and function, which was reflected in the outcome of all tests investigated in this study.…”