Protamines and spermatogenesis inDrosophilaandHomo sapiens

Kanippayoor, Rachelle L.; Alpern, Joshua H. M.; Moehring, Amanda J.

doi:10.4161/spmg.24376

Cited by 48 publications

(47 citation statements)

References 77 publications

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“…We thus wondered whether DHD was involved in the reduction of putative disulfide bonds present on sperm chromatin. Remarkably, all four Drosophila SNBPs identified so far show conserved cysteine residues, thus opening the possibility that they could be involved in the formation of disulfide bonds in a way similar to mammalian protamines (refs 31, 32, 40, 41; Supplementary Fig. 5).…”

Section: Resultsmentioning

confidence: 99%

Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila

et al. 2016

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In most animals, the extreme compaction of sperm DNA is achieved after the massive replacement of histones with sperm nuclear basic proteins (SNBPs), such as protamines. In some species, the ultracompact sperm chromatin is stabilized by a network of disulfide bonds connecting cysteine residues present in SNBPs. Studies in mammals have established that the reduction of these disulfide crosslinks at fertilization is required for sperm nuclear decondensation and the formation of the male pronucleus. Here, we show that the Drosophila maternal thioredoxin Deadhead (DHD) is specifically required to unlock sperm chromatin at fertilization. In dhd mutant eggs, the sperm nucleus fails to decondense and the replacement of SNBPs with maternally-provided histones is severely delayed, thus preventing the participation of paternal chromosomes in embryo development. We demonstrate that DHD localizes to the sperm nucleus to reduce its disulfide targets and is then rapidly degraded after fertilization.

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Section: Resultsmentioning

confidence: 99%

Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila

et al. 2016

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“…Sperm DNA is compacted primarily by small arginineand cysteine-rich proteins termed protamines (Kanippayoor et al 2013). Thus, the structure of protamine-based chromatin of haploid sperm cells is fundamentally different from that of oligonucleosome-based somatic cell chromatin (Balhorn 1982;Braun 2001).…”

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confidence: 99%

“…It allows for a striking degree of nuclear compaction to maintain the paternal genome integrity and promote sperm motility (Miller et al 2010;Rathke et al 2014). Drosophila male-specific transcripts of protamine A (ProtA) and ProtB encode protamine-like proteins that exhibit homology with mammalian protamines and constitute the major protein component of sperm chromatin (Raja and Renkawitz-Pohl 2005;Alvi et al 2013;Kanippayoor et al 2013). After egg fertilization, sperm chromatin undergoes remodeling (Loppin et al 2015), whereupon protamines are expelled from DNA by the combined action of a family of protamine chaperones (Emelyanov et al 2014) and replaced by core histones in a process dependent on the histone chaperone HIRA (Loppin et al 2005) and the ATP-driven motor protein CHD1 (Konev et al 2007).…”

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confidence: 99%

Thioredoxin-dependent disulfide bond reduction is required for protamine eviction from sperm chromatin

Emelyanov

Fyodorov

2016

Genes Dev.

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Cysteine oxidation in protamines leads to their oligomerization and contributes to sperm chromatin compaction. Here we identify the Drosophila thioredoxin Deadhead (DHD) as the factor responsible for the reduction of intermolecular disulfide bonds in protamines and their eviction from sperm during fertilization. Protamine chaperone TAP/p32 dissociates DNA-protamine complexes in vitro only when protamine oligomers are first converted to monomers by DHD. dhd-null embryos cannot decondense sperm chromatin and terminate development after the first pronuclear division. Therefore, the thioredoxin DHD plays a critical role in early development to facilitate the switch from protamine-based sperm chromatin structures to the somatic nucleosomal chromatin.

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“…In many species, including Drosophila melanogaster and mammalian species, the morphological changes of the germ cells are accompanied by a remarkable epigenetic rearrangement of the haploid male germ-line chromatin, called the histone-to-protamine switch (H-P switch) [6][7][8][9] . Possibly nearly all canonical histone and many histone-variant molecules are stripped from the DNA and are replaced by small basic proteins, the protamines, resulting in the highly compact nucleoprotamine structure specific to the chromatin of mature sperm.…”

Section: Introductionmentioning

confidence: 99%

Ex vivo Culture of Drosophila Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

Gärtner

Rathke

Renkawitz‐Pohl

et al. 2014

JoVE

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During spermatogenesis in mammals and in Drosophila melanogaster, male germ cells develop in a series of essential developmental processes. This includes differentiation from a stem cell population, mitotic amplification, and meiosis. In addition, post-meiotic germ cells undergo a dramatic morphological reshaping process as well as a global epigenetic reconfiguration of the germ line chromatin-the histone-toprotamine switch.Studying the role of a protein in post-meiotic spermatogenesis using mutagenesis or other genetic tools is often impeded by essential embryonic, pre-meiotic, or meiotic functions of the protein under investigation. The post-meiotic phenotype of a mutant of such a protein could be obscured through an earlier developmental block, or the interpretation of the phenotype could be complicated. The model organism Drosophila melanogaster offers a bypass to this problem: intact testes and even cysts of germ cells dissected from early pupae are able to develop ex vivo in culture medium. Making use of such cultures allows microscopic imaging of living germ cells in testes and of germ-line cysts. Importantly, the cultivated testes and germ cells also become accessible to pharmacological inhibitors, thereby permitting manipulation of enzymatic functions during spermatogenesis, including post-meiotic stages.The protocol presented describes how to dissect and cultivate pupal testes and germ-line cysts. Information on the development of pupal testes and culture conditions are provided alongside microscope imaging data of live testes and germ-line cysts in culture. We also describe a pharmacological assay to study post-meiotic spermatogenesis, exemplified by an assay targeting the histone-to-protamine switch using the histone acetyltransferase inhibitor anacardic acid. In principle, this cultivation method could be adapted to address many other research questions in pre-and post-meiotic spermatogenesis.

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Protamines and spermatogenesis inDrosophilaandHomo sapiens

Cited by 48 publications

References 77 publications

Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila

Unlocking sperm chromatin at fertilization requires a dedicated egg thioredoxin in Drosophila

Thioredoxin-dependent disulfide bond reduction is required for protamine eviction from sperm chromatin

<em>Ex vivo</em> Culture of <em>Drosophila</em> Pupal Testis and Single Male Germ-line Cysts: Dissection, Imaging, and Pharmacological Treatment

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