RNF8-dependent histone ubiquitination during DNA damage response and spermatogenesis

Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109, USA.
Acta Biochimica et Biophysica Sinica (Impact Factor: 2.19). 03/2011; 43(5):339-45. DOI: 10.1093/abbs/gmr016
Source: PubMed


Histone ubiquitination regulates the chromatin structure that is important for many biological processes. Recently, ubiquitination
of histones was observed during the DNA damage response (DDR), and this modification is controlled by really interesting new
gene (RING) domain E3 ligase, RNF8. Together with the E2 conjugating enzyme UBC13, RNF8 catalyzes ubiquitination of the histones
H2A and H2AX during the DDR, thus facilitating downstream recruitment of DDR factors, such as p53 binding protein 1 (53BP1)
and breast cancer type 1 susceptibility protein (BRCA1), to the damage site. Accordingly, the RNF8 knockout mice display phenotypes
associated with failed DDR, including hypersensitivity to ionizing radiation, V(D)J recombination deficiency, and a predisposition
to cancer. In addition to the DDR phenotypes, RNF8 knockout mice fail to generate mature sperm during spermatogenesis, resulting
in male sterility. The RNF8 knockout mice also have a drastic reduction in histone ubiquitination in the testes. These findings
indicate that the role of histone ubiquitination during chromatin remodeling in two different biological events could be linked
by an RNF8-dependent mechanism. Here, we review the molecular mechanism of RNF8-dependent histone ubiquitination both in DDR
and spermatogenesis.

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    • "However, Ac-H4 was significantly upregulated in the elongating spermatids of animals following a 9-wk recovery period, compared to saline-treated counterparts; furthermore, this increased expression was also found with a similar 3-fold change in spermatozoa, although statistical significance was not attained. We assessed the protein expression of another modulator of histone displacement, RNF8 (ring finger protein 8), an E3 ubiquitin-protein ligase shown to aid nucleosome removal by preferentially ubiquitinating histone H2A/H2B and promoting the recruitment of acetyl groups to neighboring histone H4[23,24]. BEP treatment did not alter the protein expression of RNF8 in any cell type when compared to saline-treated controls (Fig. 1B). Following a 9-wk recovery period from BEP treatment, elongating spermatids showed an increasing trend in RNF8 expression; this difference was significant in spermatozoa. "
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    ABSTRACT: During spermiogenesis histones are replaced first by transition proteins and then by protamines resulting in a very condensed sperm DNA structure that is absolutely critical for normal sperm function. We have demonstrated previously that, despite a 9-wk recovery period, mature sperm from rats treated for 9 wk with bleomycin, etoposide, and cis-platinum (BEP), the drugs used to treat testicular cancer, have reduced levels of protamine 1 and a concomitant upregulation of specific histones, highlighting a problem in histone eviction. Here, we demonstrate that regulators of histone removal are increased in elongating spermatids following recovery; however, Ac-H4 and gammaH2AX histones remain elevated in elongating spermatids or caudal epididymal spermatozoa 9 wk post-BEP treatment. This indicates that chromatin remodelers and effector proteins that respond to histone removal cues may be a target of BEP treatment. A decrease in the expression of SMARCE1 in elongating spermatids may explain the persistent retention of histones in cauda epididymal sperm 9 wk after the cessation of BEP treatment. Remarkably, proteins implicated in the translational control and post-translational processing of protamine 1 are also significantly elevated 9 wk post-BEP treatment, suggesting that histone eviction may dictate the DNA availability for protamine binding. Males mated to control females 9 wk after BEP-treatment have reduced litter sizes; moreover, the profile of gene expression in the developing testes of their pups is altered. Altering the proportion of histones to protamine in mature spermatozoa has an adverse impact on male fecundity, with modifications to epigenetic marks potentially threatening normal progeny development.
    No preview · Article · Aug 2013 · Biology of Reproduction
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    • "Interestingly, mutant spermatocytes deficient for E3 ligase RNF8 show normal MSCI and meiotic progression despite the absence of ubiH2A and ubiquitin conjugates in the sex body (Lu et al., 2010; Ma et al., 2011). Histone modifications show dynamic spatiotemporal patterns during prophase I, suggesting an important role during meiosis. "
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    ABSTRACT: Meiosis is one of the most critical developmental processes in sexually reproducing organisms. One round of DNA replication followed by two rounds of cell divisions results in generation of haploid gametes (sperm and eggs in mammals). Meiotic failure typically leads to infertility in mammals. In the process of meiotic recombination, maternal and paternal genomes are shuffled, creating new allelic combinations and thus genetic variety. However, in order to achieve this, meiotic cells must self-inflict DNA damage in the form of programmed double-strand breaks (DSBs). Complex processes evolved to ensure proper DSB repair, and to do so in a way that favors interhomolog reciprocal recombination and crossovers. The hallmark of meiosis, a structurally conserved proteinaceous structure called the synaptonemal complex, is found only in meiotic cells. Conversely, meiotic homologous recombination is an adaptation of the mitotic DNA repair process but involving specialized proteins. In this chapter, we summarize current developments in mammalian meiosis enabled by genetically modified mice.
    Full-text · Article · Aug 2012 · International review of cell and molecular biology
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    • "GRTH associated mRNA messages of histone cluster 1, H2AB/H2AE also link to ubiquitin-like modifier activating enzyme 1 (UBA1) and further extend to the ubiquin network signaling (Fig. 1A, Nt.1). Because of the essential role of histone ubiquitination in the chromatin remodeling to permit transition proteins /protamines replacement leading to final mature germ cell production [21], [22], [23], this GRTH-histone-ubiquitin network offers an additional regulatory route of GRTH action to be explored during spermatogenesis. "
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    ABSTRACT: Gonadotropin Regulated Testicular RNA Helicase (GRTH/Ddx25) is a testis-specific multifunctional RNA helicase and an essential post-transcriptional regulator of spermatogenesis. GRTH transports relevant mRNAs from nucleus to cytoplasmic sites of meiotic and haploid germ cells and associates with actively translating polyribosomes. It is also a negative regulator of steroidogenesis in Leydig cells. To obtain a genome-wide perspective of GRTH regulated genes, in particularly those associated with polyribosomes, microarray differential gene expression analysis was performed using polysome-bound RNA isolated from testes of wild type (WT) and GRTH KO mice. 792 genes among the entire mouse genome were found to be polysomal GRTH-linked in WT. Among these 186 were down-regulated and 7 up-regulated genes in GRTH null mice. A similar analysis was performed using total RNA extracted from purified germ cell populations to address GRTH action in individual target cells. The down-regulation of known genes concerned with spermatogenesis at polysomal sites in GRTH KO and their association with GRTH in WT coupled with early findings of minor or unchanged total mRNAs and abolition of their protein expression in KO underscore the relevance of GRTH in translation. Ingenuity pathway analysis predicted association of GRTH bound polysome genes with the ubiquitin-proteasome-heat shock protein signaling network pathway and NFκB/TP53/TGFB1 signaling networks were derived from the differentially expressed gene analysis. This study has revealed known and unexplored factors in the genome and regulatory pathways underlying GRTH action in male reproduction.
    Full-text · Article · Mar 2012 · PLoS ONE
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