Etoposide interferes with the process of chromatin condensation during alga Chara vulgaris spermiogenesis

Wojtczak, Agnieszka

doi:10.1016/j.micron.2014.03.015

Cited by 7 publications

(15 citation statements)

References 41 publications

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“…In pachytene spermatocytes and in the absence of DNA breaks, γH2AX is detected in the sex body, and thought to be produced by ATR (Carofiglio et al, 2013;Fernandez-Capetillo et al, 2003;Mahadevaiah et al, 2001;Turner et al, 2004). In elongating spermatids, γH2AX foci and transitory DNA breaks occur simultaneously (Agnieszka, 2014;Govin et al, 2004;Leduc et al, 2008b;Marcon and Boissonneault, 2004;Rathke et al, 2014;Wojtczak et al, 2008), but the kinase responsible for the H2AX phosphorylation and the role of γH2AX in spermiogenesis is not clearly understood.…”

Section: Introductionmentioning

confidence: 99%

TSSK6 is required for γH2AX formation and the histone-to-protamine transition during spermiogenesis

Jha

Tripurani

Johnson

2017

Journal of Cell Science

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Spermiogenesis includes transcriptional silencing, chromatin condensation and extensive morphological changes as spermatids transform into sperm. Chromatin condensation involves histone hyperacetylation, transitory DNA breaks, histone H2AX (also known as H2AFX) phosphorylation at Ser139 (γH2AX), and replacement of histones by protamines. Previously, we have reported that the spermatid protein kinase TSSK6 is essential for fertility in mice, but its specific role in spermiogenesis is unknown. Here, we show that TSSK6 expression is spatiotemporally coincident with γH2AX formation in the nuclei of developing mouse spermatids. RNAsequencing analysis demonstrates that genetic ablation of Tssk6 does not impact gene expression or silencing in spermatids. However, loss of TSSK6 blocks γH2AX formation, even though the timing and level of the transient DNA breaks is unaltered. Further, Tssk6-knockout sperm contained increased levels of histones H3 and H4, and protamine 2 precursor and intermediate(s) indicative of a defective histone-to-protamine transition. These results demonstrate that TSSK6 is required for γH2AX formation during spermiogenesis, and also link γH2AX to the histone-to-protamine transition and male fertility.

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Section: Introductionmentioning

confidence: 99%

TSSK6 is required for γH2AX formation and the histone-to-protamine transition during spermiogenesis

Jha

Tripurani

Johnson

2017

Journal of Cell Science

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“…In the green algae Chara vulgaris , the topoisomerase inhibitor etoposide interferes with post-meiotic γH2AX formation and spermatogenesis (Agnieszka and Wojtczak, 2014). This observation was interpreted as demonstrating a need for transient Top2-induced DSBs to exchange nucleoproteins.…”

Section: Discussionmentioning

confidence: 99%

Post-meiotic DNA double-strand breaks occur in Tetrahymena, and require Topoisomerase II and Spo11

Akematsu

Fukuda

Garg

et al. 2017

eLife

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Based on observations of markers for DNA lesions, such as phosphorylated histone H2AX (γH2AX) and open DNA ends, it has been suggested that post-meiotic DNA double-strand breaks (PM-DSBs) enable chromatin remodeling during animal spermiogenesis. However, the existence of PM-DSBs is unconfirmed, and the mechanism responsible for their formation is unclear. Here, we report the first direct observation of programmed PM-DSBs via the electrophoretic separation of DSB-generated DNA fragments in the ciliate Tetrahymena thermophila. These PM-DSBs are accompanied by switching from a heterochromatic to euchromatic chromatin structure in the haploid pronucleus. Both a topoisomerase II paralog with exclusive pronuclear expression and Spo11 are prerequisites for PM-DSB induction. Reduced PM-DSB induction blocks euchromatin formation, characterized by histone H3K56 acetylation, leading to a failure in gametic nuclei production. We propose that PM-DSBs are responsible for histone replacement during the reprogramming of generative to undifferentiated progeny nuclei.DOI: http://dx.doi.org/10.7554/eLife.26176.001

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“…The solution of the inhibitor was prepared with the water from the natural environment, with DMSO (Sigma) in the ratio 20 mg/mL. These duration times of treatment with the bromodomain inhibitor were used, because previous analyses [3,28] were also based on the same scheme. In the studies on animal material, using cell lines, a broad concentration range of bromodomain inhibitors, but lower than in this alga, was used.…”

Section: Treatment With Bromodomain Inhibitormentioning

confidence: 99%

“…It lasts 7 days during which 10 stages (I-X) of different duration times are distinguished. During each of the stages, there are characteristic ultrastructural changes [1] that are the result, among others, of the presence of double-strand DNA breaks that allow the exchange of histones to protamines, conditioning correct chromatin remodeling [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…Bromodomains bind acetylated lysines, which are present in various proteins i.e., histones playing an important role in chromatin organization during spermiogenesis [27]. The results of previous immunofluorescent and ultrastructural analyses showed that blocking the removal of histones, during the exchange of these proteins into protamines, hindered the proper course of spermiogenesis [3,28]. The studies of spermatogenesis concerning Brdt gene in two fish species, which have different methods of nuclear protein exchange, revealed variations in this gene expression which could indicate a different role of Brdt protein [29].…”

Section: Introductionmentioning

confidence: 99%

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Blocking the Bromodomains Function Contributes to Disturbances in Alga Chara vulgaris Spermatids Differentiation

Wojtczak

2020

Cells

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Bromodomain containing (BRD) proteins play an essential role in many cellular processes. The aim of this study was to estimate activity of bromodomains during alga Chara vulgaris spermatids differentiation. The effect of a bromodomain inhibitor, JQ1 (100 μM), on the distribution of individual stages of spermatids and their ultrastructure was studied. The material was Feulgen stained and analysed in an electron microscope. JQ1 caused shortening of the early stages of spermiogenesis and a reverse reaction at the later stages. Additionally, in the same antheridium, spermatids at distant developmental stages were present. On the ultrastructural level, chromatin fibril system disorders and significantly distended endoplasmic reticulum (ER) cisternae already at the early stages were observed. Many autolytic vacuoles were also visible. The ultrastructural disturbances intensified after prolonged treatment with JQ1. The obtained data show that JQ1 treatment led to changes in the spermatid number and disturbances in chromatin condensation and to cytoplasm reduction. The current studies show some similarities between C. vulgaris and mammals spermiogenesis. Taken together, these results suggest that JQ1 interferes with the spermatid differentiation on many interdependent levels and seems to induce ER stress, which leads to spermatid degeneration. Studies on the role of bromodomains in algae spermiogenesis have not been conducted so far.

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Etoposide interferes with the process of chromatin condensation during alga Chara vulgaris spermiogenesis

Cited by 7 publications

References 41 publications

TSSK6 is required for γH2AX formation and the histone-to-protamine transition during spermiogenesis

TSSK6 is required for γH2AX formation and the histone-to-protamine transition during spermiogenesis

Post-meiotic DNA double-strand breaks occur in Tetrahymena, and require Topoisomerase II and Spo11

Blocking the Bromodomains Function Contributes to Disturbances in Alga Chara vulgaris Spermatids Differentiation

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