Developmental regulation of cell type-specific transcription by novel promoter-proximal sequence elements.

Cell type-specific transcriptional programs that drive differentiation of specialized cell types are key players in development and tissue regeneration. One of the most dramatic changes in the transcription program in occurs with the transition from proliferating spermatogonia to differentiating spermatocytes, with >3000 genes either newly expressed or expressed from new alternative promoters in spermatocytes. Here we show that opening of these promoters from their closed state in precursor cells requires function of the spermatocyte-specific tMAC complex, localized at the promoters.

Polycomb protein SCML2 facilitates H3K27me3 to establish bivalent domains in the male germline.

Repressive H3K27me3 and active H3K4me2/3 together form bivalent chromatin domains, molecular hallmarks of developmental potential. In the male germline, these domains are thought to persist into sperm to establish totipotency in the next generation. However, it remains unknown how H3K27me3 is established on specific targets in the male germline.

Elucidation of the Fanconi Anemia Protein Network in Meiosis and Its Function in the Regulation of Histone Modifications.

Precise epigenetic regulation of the sex chromosomes is vital for the male germline. Here, we analyze meiosis in eight mouse models deficient for various DNA damage response (DDR) factors, including Fanconi anemia (FA) proteins. We reveal a network of FA and DDR proteins in which FA core factors FANCA, FANCB, and FANCC are essential for FANCD2 foci formation, whereas BRCA1 (FANCS), MDC1, and RNF8 are required for BRCA2 (FANCD1) and SLX4 (FANCP) accumulation on the sex chromosomes during meiosis.

Poised chromatin and bivalent domains facilitate the mitosis-to-meiosis transition in the male germline.

Background: The male germline transcriptome changes dramatically during the mitosis-to-meiosis transition to activate late spermatogenesis genes and to transiently suppress genes commonly expressed in somatic lineages and spermatogenesis progenitor cells, termed somatic/progenitor genes.

Results: These changes reflect epigenetic regulation. Induction of late spermatogenesis genes during spermatogenesis is facilitated by poised chromatin established in the stem cell phases of spermatogonia, whereas silencing of somatic/progenitor genes during meiosis and postmeiosis is associated with formation of bivalent domains which also allows the recovery of the somatic/progenitor program after fertilization.

FANCB is essential in the male germline and regulates H3K9 methylation on the sex chromosomes during meiosis.

Fanconi anemia (FA) is a recessive X-linked and autosomal genetic disease associated with bone marrow failure and increased cancer, as well as severe germline defects such as hypogonadism and germ cell depletion. Although deficiencies in FA factors are commonly associated with germ cell defects, it remains unknown whether the FA pathway is involved in unique epigenetic events in germ cells. In this study, we generated Fancb mutant mice, the first mouse model of X-linked FA, and identified a novel function of the FA pathway in epigenetic regulation during mammalian gametogenesis.

SCML2 establishes the male germline epigenome through regulation of histone H2A ubiquitination.

Gametogenesis is dependent on the expression of germline-specific genes. However, it remains unknown how the germline epigenome is distinctly established from that of somatic lineages. Here we show that genes commonly expressed in somatic lineages and spermatogenesis-progenitor cells undergo repression in a genome-wide manner in late stages of the male germline and identify underlying mechanisms.

The great escape: Active genes on inactive sex chromosomes and their evolutionary implications.

Epigenetic mechanisms precisely regulate sex chromosome inactivation as well as genes that escape the silencing process. In male germ cells, DNA damage response factor RNF8 establishes active epigenetic modifications on the silent sex chromosomes during meiosis, and activates escape genes during a state of sex chromosome-wide silencing in postmeiotic spermatids. During the course of evolution, the gene content of escape genes in postmeiotic spermatids recently diverged on the sex chromosomes.

RNF8 regulates active epigenetic modifications and escape gene activation from inactive sex chromosomes in post-meiotic spermatids.

Sex chromosomes are uniquely subject to chromosome-wide silencing during male meiosis, and silencing persists into post-meiotic spermatids. Against this background, a select set of sex chromosome-linked genes escapes silencing and is activated in post-meiotic spermatids. Here, we identify a novel mechanism that regulates escape gene activation in an environment of chromosome-wide silencing in murine germ cells.

Sex chromosome inactivation in germ cells: emerging roles of DNA damage response pathways.

Sex chromosome inactivation in male germ cells is a paradigm of epigenetic programming during sexual reproduction. Recent progress has revealed the underlying mechanisms of sex chromosome inactivation in male meiosis. The trigger of chromosome-wide silencing is activation of the DNA damage response (DDR) pathway, which is centered on the mediator of DNA damage checkpoint 1 (MDC1), a binding partner of phosphorylated histone H2AX (γH2AX).

Human postmeiotic sex chromatin and its impact on sex chromosome evolution.

Sex chromosome inactivation is essential epigenetic programming in male germ cells. However, it remains largely unclear how epigenetic silencing of sex chromosomes impacts the evolution of the mammalian genome. Here we demonstrate that male sex chromosome inactivation is highly conserved between humans and mice and has an impact on the genetic evolution of human sex chromosomes.

A novel Y chromosome microdeletion with the loss of an endogenous retrovirus related, testis specific transcript in AZFb region.

Purpose: We identified the endogenous retroviruses associated with TTYs (testis specific transcripts linked to the Y) in the AZFb region. We evaluated the relationship between endogenous retroviruses, and TTY expression patterns and function in spermatogenesis.

Materials And Methods: We identified family members of TTYs in the AZFb region using computational screening.

Human endogenous retrovirus K14C drove genomic diversification of the Y chromosome during primate evolution.

The male-specific region of Y chromosome (MSY) has accumulated a higher density of human endogenous retroviruses (HERVs) and related sequences when compared with other regions of the human genome. Here, we focused on one HERV family, HERV-K14C that seemed to integrate preferentially into the Y chromosome in humans. To identify every copies of HERV-K14C in the human genome, we applied computational screening to map precisely the locus of individual HERV-K14C copies.

Features of constitutive gr/gr deletion in a Japanese population.

Background: The relationship between male infertility and gr/gr deletions that remove multiple genes of the Y chromosome varies among countries and populations. The aim of this study was to investigate the association between gr/gr deletions and spermatogenic phenotype in fertile and infertile Japanese men.

Methods: The subjects were screened by sequence-tagged site (STS) analysis to detect gr/gr deletions, and haplogroups were assigned using eight highly informative markers.

Azoospermia factor and male infertility.

Recently, work has shown that azoospermia factor (AZF) microdeletions result from homologous recombination between almost identical blocks in this gene region. These microdeletions in the Y chromosome are a common molecular genetic cause of spermatogenetic failure leading to male infertility. After completion of the sequencing of the Y chromosome, the classical definition of AZFa, AZFb, and AZFc was modified to five regions, namely AZFa, P5/proximal-P1, P5/distal-P1, P4/distal-P1, and AZFc, as a result of the determination of Y chromosomal structure.

Measurement-specific bioavailable testosterone using concanavalin A precipitation: comparison of calculated and assayed bioavailable testosterone.

Objective: To assess the value of calculated bioavailable testosterone (cBT) and assayed BT (aBT) for the diagnosis of late-onset hypogonadism (LOH) in middle-aged and elderly subjects.

Methods: In order to assay serum BT, sex hormone-binding globulin was precipitated with concanavalin-A and then testosterone was measured using liquid chromatography-tandem mass spectrometry. To validate the non-sex-hormone-binding-globulin-bound testosterone, gel filtration chromatography and concanavalin-A sepharose were used.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of salivary testosterone and cortisol in healthy men for utilization in the diagnosis of late-onset hypogonadism in males.

It is well known that late-onset hypogonadism in males can cause a variety of symptoms, and the differential diagnosis is relatively difficult, including psychological disorders, stress, and mood disturbances. The level of serum cortisol can be measured to reflect a patient's level of stress. Salivary hormones facilitate the evaluation of physiological hormonal actions based on free hormone assay.

Tissue-specific differentially methylated regions of the human VASA gene are potentially associated with maturation arrest phenotype in the testis.

Numerous CpG islands containing tissue-specific differentially methylated regions (TDMRs) are potential methylation sites in normal cells and tissues. The VASA (also known as DDX4) gene is believed to be under the control of TDMRs. A total of 131 male patients with idiopathic azoospermia or severe oligospermia were evaluated histologically, and the methylation status of CpG islands in the VASA gene was screened.

Single nucleotide polymorphism analysis of the follicle-stimulating hormone (FSH) receptor in Japanese with male infertility: identification of codon combination with heterozygous variations of the two discrete FSH receptor gene.

Aims: Dysfunction of the FSH receptor (FSHR) may be involved in some form of male infertility with azoospermia or oligozoospermia. We assessed the discrete codon combination with homo/heterozygous variation of the exon 10 in the FSHR gene.

Methods: The genotype of codon 307 and codon 680 were analysed in 352 patients with idiopathic male infertility and 145 men with proven fertility.

Endogenous retrovirus-related sequences provide an alternative transcript of MCJ genes in human tissues and cancer cells.

The MCJ gene is a member of the DNAJ family, and its transcriptional event is controlled by methylation of the CpG island. In our study, we found LTR33 and LTR7 elements provided an alternative transcript within the MCJ gene. To detect different expression patterns between the originally reported MCJ transcript and the LTR-related transcript, we performed a RT-PCR approach using various human tissues and cancer cells.

Molecular evolution of the periphilin gene in relation to human endogenous retrovirus m element.

HERV-M (human endogenous retrovirus M), related to the super family of HERV-K, has a methionine (M) tRNA primer-binding site, and is located within the periphilin gene on human chromosome 12q12. HERV-M has been integrated into the periphilin gene as the truncated form, 5'LTR-gag-pol-3'LTR. Polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) approaches were conducted to investigate its evolutionary origins.