Sequential Expression of Nucleoproteins during Rat Spermiogenesis

Ws, Kistler; Henriksén, K.; Mali, Pekka; Parvinen, Martti

doi:10.1006/excr.1996.0188

Cited by 96 publications

(69 citation statements)

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“…At step 13, the transition proteins are completely replaced by protamines (Kistler et al 1996). These replaced nucleoproteins also might be degraded in the CBs within a limited period.…”

Section: Discussionmentioning

confidence: 99%

Chromatoid Bodies: Aggresome-like Characteristics and Degradation Sites for Organelles of Spermiogenic Cells

Haraguchi

Mabuchi

Hirata

et al. 2005

J Histochem Cytochem.

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S U M M A R YWe investigated the localization of several markers for lysosomes and aggresomes in the chromatoid bodies (CBs) by immunoelectron microscopy. We found so-called aggresomal markers such as Hsp70 and ubiquitin in the core of the CBs and vimentin and proteasome subunit around the CBs. Ubiquitin-conjugating enzyme (E2) was also found in the CBs. In tubulovesicular structures surrounding the CBs, lysosomal markers were detected but an endoplasmic reticulum retention signal (KDEL) was not. Moreover, proteins located in each subcellular compartment, including the cytosol, mitochondria, and nucleus, were detected in the CBs. Signals for cytochrome oxidase I (COXI) coded on mitochondrial DNA were also found in the CBs. Quantitative analysis of labeling density showed that all proteins examined were concentrated in the CBs to some extent. These results show that the CBs have some aggresomal features, suggesting that they are not a synthetic site as proposed previously but a degradation site where unnecessary DNA, RNA, and proteins are digested.

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“…At step 13, the transition proteins are completely replaced by protamines (Kistler et al 1996). These replaced nucleoproteins also might be degraded in the CBs within a limited period.…”

Section: Discussionmentioning

confidence: 99%

Chromatoid Bodies: Aggresome-like Characteristics and Degradation Sites for Organelles of Spermiogenic Cells

Haraguchi

Mabuchi

Hirata

et al. 2005

J Histochem Cytochem.

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“…Protein samples (20 g) extracted from adult mice testes were subjected to Western analysis with GRTH antibody (7) or other antibodies indicated (Santa Cruz Biotechnology). Polyclonal antisera for rat transition proteins 1 (Tp1) and 2 (Tp2) were kindly provided by S. Kistler (University of South Carolina, Columbia) (9), and a 17␣-hydroxylase antiserum was generated in our laboratory (10).…”

Section: Methodsmentioning

confidence: 99%

Gonadotropin-regulated testicular RNA helicase (GRTH/Ddx25) is essential for spermatid development and completion of spermatogenesis

Tsai‐Morris

Lee

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

151

175

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Gonadotropin-regulated testicular RNA helicase (GRTH͞Ddx25), a member of the DEAD-box protein family, is a testis-specific gonadotropin-regulated RNA helicase that is present in Leydig cells and germ cells (meiotic spermatocytes and spermatids). In this study, we observed that GRTH is present in the nucleus, cytoplasm and chromatoid body of germ cells, and is an integral component of messenger ribonuclear protein particles. Male mice with a null mutation in the GRTH gene displayed normal gonadotropin and androgen profiles. However, they were sterile, with azoospermia caused by a complete arrest of spermiogenesis at step 8 of round spermatids and failure to elongate. Round spermatids of the null mice showed marked diminution in the size of chromatoid bodies. The transcription of relevant messages was not altered, but their translation was abrogated in a selective manner. Protein expression of transition proteins 1 and 2 and angiotensin-converting enzyme was completely absent, whereas that of the transcriptional activator cAMP responsive element modulator was intact. These findings indicate that GRTH participates in translational-associated events during germ cell development. Although significant apoptosis was present at the metaphase of meiosis in the GRTH-null mice, spermatogenesis proceeded to step 8 of spermiogenesis when complete arrest occurred. This progression may relate to compensatory gene function(s) and͞or the observed up-regulation of DNA repair proteins Rad51 and Dmc1. This study (i) demonstrates that GRTH is essential for completion of spermatogenesis, (ii) provides insights into intrinsic requirements for spermiogenesis, and (iii) establishes a model for studies of male infertility and contraception.messenger ribonuclear protein particle ͉ translation ͉ testis ͉ spermiogenesis ͉ sterility S permatogenesis is a complex process that depends on the integrated expression of an array of genes that must operate in a precise temporal sequence to produce normal mature spermatozoa (1, 2). Gene expression in haploid spermatids requires temporal uncoupling of transcription and translation. Two-thirds of the mRNAs in the adult mammalian testes are associated with specific proteins to form messenger ribonuclear protein (mRNP) particles and stored in the cytoplasm of spermatids (3). Translational activation of stored mRNAs at specific times is essential for the completion of spermatogenesis. Modulation of RNA structure by members of the DEAD-box family of RNA helicases is a crucial step in many different fundamental biological processes (4,5). This class of proteins participates in various aspects of RNA metabolism and translational events. However, little is known about the involvement of DEAD-box proteins in testicular germ cell development.Gonadotropin-regulated testicular RNA helicase (GRTH͞ Ddx25), a member of the DEAD-box protein family of RNA helicases, was cloned and characterized in our laboratory (6-8). This enzyme, which only shares 30-40% similarity with other helicases, including those predominantl...

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“…The Tnp2 mRNA is expressed in step 7-12 spermatids, and is translationally repressed in steps 7 and 8 and translationally active starting in step 9 (Kistler et al 1996). Saunders et al (1992) observed that the Tnp2 mRNA is strongly localized adjacent to the nucleus in step 7 using digoxigenin-based non-isotopic in situ hybridization, fixation by perfusion with Bouin's, and 2 mm polystyrene sections.…”

Section: Introductionmentioning

confidence: 99%

Maybe repressed mRNAs are not stored in the chromatoid body in mammalian spermatids

Kleene

Cullinane²

2011

Reproduction

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The chromatoid body is a dynamic organelle that is thought to coordinate the cytoplasmic regulation of mRNA translation and degradation in mammalian spermatids. The chromatoid body is also postulated to function in repression of mRNA translation by sequestering dormant mRNAs where they are inaccessible to the translational apparatus. This review finds no convincing evidence that dormant mRNAs are localized exclusively in the chromatoid body. This discrepancy can be explained by two hypotheses. First, experimental artifacts, possibly related to peculiarities of the structure and function of the chromatoid body, preclude obtaining an accurate indication of mRNA localization. Second, mRNA is not stored in the chromatoid body, because, like perinuclear P granules in Caenorhabditis elegans, the chromatoid body functions as a center for mRNP remodeling and export to other cytoplasmic sites.

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Sequential Expression of Nucleoproteins during Rat Spermiogenesis

Cited by 96 publications

References 0 publications

Chromatoid Bodies: Aggresome-like Characteristics and Degradation Sites for Organelles of Spermiogenic Cells

Chromatoid Bodies: Aggresome-like Characteristics and Degradation Sites for Organelles of Spermiogenic Cells

Gonadotropin-regulated testicular RNA helicase (GRTH/Ddx25) is essential for spermatid development and completion of spermatogenesis

Maybe repressed mRNAs are not stored in the chromatoid body in mammalian spermatids

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