Two novel mouse genes mapped to chromosome Yp are expressed specifically in spermatids (original) (raw)
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Deletions on mouse Yq lead to upregulation of multiple X- and Y-linked transcripts in spermatids
Human Molecular Genetics, 2005
Deletions on the mouse Y-chromosome long arm (MSYq) lead to teratozoospermia and in severe cases to infertility. We find that the downstream transcriptional changes in the testis resulting from the loss of MSYq-encoded transcripts involve upregulation of multiple X-and Y-linked spermatid-expressed genes, but not related autosomal genes. Therefore, this indicates that in normal males, there is a specific repression of X and Y (gonosomal) transcription in post-meiotic cells, which depends on MSYq-encoded transcripts. Together with the known sex ratio skew in favour of females in the offspring of fertile MSYqdel males, this strongly suggests the existence of an intragenomic conflict between X-and Y-linked genes. Two potential antagonists in this conflict are the X-linked multicopy gene Xmr and its multicopy MSYq-linked relative Sly, which are upregulated and downregulated, respectively, in the testes of MSYqdel males. Xmr is also expressed during meiotic sex chromosome inactivation (MSCI), indicating a link between the MSCI and the MSYq-dependent gonosomal repression in spermatids. We therefore propose that this repression and MSCI itself are evolutionary adaptations to maintain a normal sex ratio in the face of X/Y antagonism.
Two genes substitute for the mouse Y chromosome for spermatogenesis and reproduction
Science (New York, N.Y.), 2016
The mammalian Y chromosome is considered a symbol of maleness, as it encodes a gene driving male sex determination, Sry, as well as a battery of other genes important for male reproduction. We previously demonstrated in the mouse that successful assisted reproduction can be achieved when the Y gene contribution is limited to only two genes, Sry and spermatogonial proliferation factor Eif2s3y. Here, we replaced Sry by transgenic activation of its downstream target Sox9, and Eif2s3y, by transgenic overexpression of its X chromosome-encoded homolog Eif2s3x. The resulting males with no Y chromosome genes produced haploid male gametes and sired offspring after assisted reproduction. Our findings support the existence of functional redundancy between the Y chromosome genes and their homologs encoded on other chromosomes.
A rat histone H4 gene closely associated with the testis-specific H1t gene
Experimental Cell Research, 1987
A rat histone H4 gene closely associated with the testis-specific Hlt gene was isolated by screening the Sargent-Bonner rat genomic library using cloned human histone genes as probes. Both the H4 gene and the Hlt gene are located on a 7-kb EcoRI genomic DNA fragment. Although the deduced amino acid sequence of the rat H4 histone is identical to that of the sequence of human histone H4, the nucleotide sequence of the coding region differs significantly from the coding region of the human H4 gene. Moreover, the relative spacing between the 5'-consensus sequence elements is unique for an H4 gene. Slnuclease protection analyses reveal that both the H4 and Hlt mRNA species are present in a fraction of rat testis cells highly enriched in pachytene spermatocytes, while only the H4 mRNA species is present in a rat myeloma cell line (Y3-Agl.2.3). During a l-h hydroxyurea treatment of the Y3 cells, which produces a 99% inhibition of DNA synthesis, the level of this H4 mRNA drops by only 50%, indicating that the stability of this mRNA is only partially coupled with DNA synthesis. @ 1987 Academic press, IIIC.
Biparental contributions of the H2A.B histone variant control embryonic development in mice
PLOS Biology, 2020
Histone variants expand chromatin functions in eukaryote genomes. H2A.B genes are testis-expressed short histone H2A variants that arose in placental mammals. Their biological functions remain largely unknown. To investigate their function, we generated a knockout (KO) model that disrupts all 3 H2A.B genes in mice. We show that H2A.B KO males have globally altered chromatin structure in postmeiotic germ cells. Yet, they do not show impaired spermatogenesis or testis function. Instead, we find that H2A.B plays a crucial role postfertilization. Crosses between H2A.B KO males and females yield embryos with lower viability and reduced size. Using a series of genetic crosses that separate parental and zygotic contributions, we show that the H2A.B status of both the father and mother, but not of the zygote, affects embryonic viability and growth during gestation. We conclude that H2A.B is a novel parental-effect gene, establishing a role for short H2A histone variants in mammalian develop...
Human Molecular Genetics, 1998
The ∆Sxr b deletion interval of the mouse Y chromosome contains Spy, a spermatogenesis factor gene(s) whose expression is essential for the postnatal development of the mitotic germ cells, spermatogonia. The boundaries of ∆Sxr b are defined by the duplicated genes Zfy1 and Zfy2 and four further genes have previously been mapped within the interval: Ube1y and Smcy, linked with Zfy1 on a contig of 250 kb, and Dffry and Uty, which were unanchored. The interval was estimated to be >450 kb. In order to identify any further gene(s) that may underlie Spy, systematic exon trapping was performed on an extended contig, anchored on Zfy1, which covers 750 kb of the ∆Sxr b interval. Exons from two novel genes were isolated and placed together with Dffry and Uty on the contig in the order Dffry-Dby-Uty-Tspy-Eif2γy-Smcy-Ube1y-Zfy1. All the genes, with the double exception of Tspy, are X-Y homologous and produce putatively functional, spliced transcripts. The tight linkage and order of Dffry, Dby and Uty was shown to be conserved in deletion intervals 5C/5D of the human Y chromosome by the construction of a contig of human PAC and YAC clones; this represents the first example of syntenic homology between Y chromosomes from two distinct mammalian orders. Interval 5C/5D contains the distal boundary of the AZFa interval, which, like ∆Sxr b , is believed to be necessary for spermatogonial development in the prepubertal testis. Our results therefore show that AZFa and Spy may be encoded by homologous genes.
Biology of Reproduction, 2001
H1t is an H1 histone variant unique to late spermatocytes and early spermatids. Using gene targeting and embryonic stem cell technologies, we have produced mice with a disrupted H1t gene. Homozygous H1t-null mice have normal fertility and show no obvious phenotypic consequence due to the lack of this histone. Biochemical and immunohistochemical approaches were used to show that normal changes in chromosomal proteins occurred during spermatid development, including the appearance and disappearance of transition proteins 1 and 2. Both protamines 1 and 2 are present in normal amounts in sonicationresistant spermatid nuclei from H1t-null mice. Analysis of H1 histones by quantitative gel electrophoresis in enriched populations of pachytene spermatocytes and round spermatids showed that the lack of H1t is only partially compensated for by somatic H1s, so that the chromatin of these cells is H1 deficient. Because H1t is thought to create a less tightly compacted chromatin environment, it may be that H1-deficient chromatin is functionally similar to chromatin with H1t present, at least with respect to permitting spermatogenesis to proceed.
Genome biology, 2005
The male-specific region of the mouse Y chromosome long arm (MSYq) is comprised largely of repeated DNA, including multiple copies of the spermatid-expressed Ssty gene family. Large deletions of MSYq are associated with sperm head defects for which Ssty deficiency has been presumed to be responsible. In a search for further candidate genes associated with these defects we analyzed changes in the testis transcriptome resulting from MSYq deletions, using testis cDNA microarrays. This approach, aided by accumulating mouse MSYq sequence information, identified transcripts derived from two further spermatid-expressed multicopy MSYq gene families; like Ssty, each of these new MSYq gene families has multicopy relatives on the X chromosome. The Sly family encodes a protein with homology to the chromatin-associated proteins XLR and XMR that are encoded by the X chromosomal relatives. The second MSYq gene family was identified because the transcripts hybridized to a microarrayed X chromosome-...
The mouse A/HeJ Y chromosome: Another good Y gone bad
2008
In both humans and mice there are numerous reports of Y chromosome abnormalities that interfere with sex determination. Recent studies in the mouse of one such mutation have identified Y chromosome nondisjunction during preimplantation development as the cause of abnormal testis determination that results in a high frequency of true hermaphroditism. We report here that the mouse Y chromosome from the A/HeJ inbred strain induces similar aberrations in sex determination. Our analyses provide evidence, however, that the mechanism underlying these aberrations is not Y chromosome nondisjunction. On the basis of our findings, we postulate that a mutation at or near the centromere affects both the segregation and sex-determining properties of the A/HeJ Y chromosome. This Y chromosome adds to the growing list of Y chromosome aberrations in humans and mice. In both species, the centromere of the Y is structurally and morphologically distinct from the centromeres of all other chromosomes. We conclude that these centromeric features make the human and mouse Y chromosomes extremely sensitive to minor structural alterations, and that our studies provide yet another example of a good Y chromosome gone Fbad._ understanding centromere dynamics is fundamental to understanding the causes of human aneuploidy. Although centromere function is highly conserved among organisms, centromere structure is subject to rapid evolution, and these structural changes play a role in speciation (Zhao et al. 2004). Little is known about variation in centromere sequence either within or among mammalian species. Nevertheless, it is clear from information about the mouse and human Y chromosomes that the Y centromere differs markedly from the centromeres of the other chromosomes in the genome. Cytogenetic banding techniques for visualizing centromeres demonstrate a single C-band negative chromosomeVthe Y chro-mosomeVin both mouse and human. In humans, the