Genetic probing of homologous recombination and non-homologous end joining during meiotic prophase in irradiated mouse spermatocytes

Ahmed, Emad A.; Philippens, M.E.P.; Kal, Henk B.; Rooij, Dirk G. de; Boer, P. de

doi:10.1016/j.mrfmmm.2010.02.004

Cited by 39 publications

(48 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It was found that c-H2AX signals appeared normally during leptotene stage and regressed during zygotene and early pachytene stages to the XY body in all genotypes (data not shown). In late pachytene and diplotene spermatocytes, in which NHEJ repair is reactivated (Ahmed et al, 2010;Goedecke et al, 1999), we noted a moderate but significantly elevated number of spermatocytes displaying on average two c-H2AX foci/late Ku70…”

Section: Hr Progression In Ku70mentioning

confidence: 69%

“…Leptotene spermatocytes show extensive histone H2AX phosphorylation in their nuclei and H2AX phosphorylation regresses with the progress of HR repair to the sex body of pachytene spermatocytes (Barchi et al, 2005;Mahadevaiah et al, 2001). Delayed repair progression at some DSB sites can lead to a few large, synaptonemal complex-associated c-H2AX foci during the late pachytene stage of prophase I (Ahmed et al, 2010;Chicheportiche et al, 2007). These foci possibly relate to delayed repair progression as shown by RPA and cH2AX colocalization in mouse and human late pachytene meiocytes (Ahmed et al, 2010;de Vries et al, 2013;Roig et al, 2004).…”

Section: Hr Progression In Ku70mentioning

confidence: 99%

“…Delayed repair progression at some DSB sites can lead to a few large, synaptonemal complex-associated c-H2AX foci during the late pachytene stage of prophase I (Ahmed et al, 2010;Chicheportiche et al, 2007). These foci possibly relate to delayed repair progression as shown by RPA and cH2AX colocalization in mouse and human late pachytene meiocytes (Ahmed et al, 2010;de Vries et al, 2013;Roig et al, 2004). To determine whether carryover of DNA damage from pre-meiotic S phase of B spermatogonia leads to altered DNA repair progression in late Ku70 2/2 spermatocytes, we examined surface-spread and SYCP3-stained Ku70-and Ku70 Rap1 doubly deficient late pachytene and diplotene spermatocytes for the presence of large cH2AX foci (Fig.…”

Section: Hr Progression In Ku70mentioning

confidence: 99%

See 2 more Smart Citations

Ku70 and non-homologous end joining protect testicular cells from DNA damage

Ahmed

Sfeir

Takai

et al. 2013

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

SummarySpermatogenesis is a complex process that generates haploid germ cells or spores and implements meiosis, a succession of two special cell divisions that are required for homologous chromosome segregation. During prophase to the first meiotic division, homologous recombination (HR) repairs Spo11-dependent DNA double-strand breaks (DSBs) in the presence of telomere movements to allow for chromosome pairing and segregation at the meiosis I division. In contrast to HR, non-homologous end joining (NHEJ), the major DSB repair mechanism during the G1 cell cycle phase, is downregulated during early meiotic prophase. At somatic mammalian telomeres, the NHEJ factor Ku70/80 inhibits HR, as does the Rap1 component of the shelterin complex. Here, we investigated the role of Ku70 and Rap1 in meiotic telomere redistribution and genome protection in spermatogenesis by studying single and double knockout mice. Ku70 2/2 mice display reduced testis size and compromised spermatogenesis, whereas meiotic telomere dynamics and chromosomal bouquet formation occurred normally in Ku70 2/2 and Ku70 2/2Rap1 D/D knockout spermatocytes. Elevated mid-preleptotene frequencies were associated with significantly increased DNA damage in Ku-deficient B spermatogonia, and in differentiated Sertoli cells. Significantly elevated levels of cH2AX foci in Ku70 2/2 diplotene spermatocytes suggest compromised progression of DNA repair at a subset of DSBs. This might explain the elevated meiotic metaphase apoptosis that is present in Ku70-deficient stage XII testis tubules, indicating spindle assembly checkpoint activation. In summary, our data indicate that Ku70 is important for repairing DSBs in somatic cells and in late spermatocytes of the testis, thereby assuring the fidelity of spermatogenesis.

show abstract

Section: Hr Progression In Ku70mentioning

confidence: 69%

Section: Hr Progression In Ku70mentioning

confidence: 99%

Section: Hr Progression In Ku70mentioning

confidence: 99%

See 1 more Smart Citation

Ku70 and non-homologous end joining protect testicular cells from DNA damage

Ahmed

Sfeir

Takai

et al. 2013

Journal of Cell Science

Self Cite

View full text Add to dashboard Cite

show abstract

“…There is increasing evidence that additional DNA repair events can be triggered during late stages of prophase I, either under normal conditions or after artificial induction of DNA damage (Goedecke et al 1999;Ahmed et al 2007). Interestingly, the mechanisms of DNA repair acting at these later stages would be preferentially nonhomologous pathways, mainly nonhomologous end joining (NHEJ) (Ahmed et al 2010). Furthermore, some telomere-associated proteins like Ku-70 have been reported to be important for the proper repair of DNA by the NHEJ pathway (Ahmed et al 2013).…”

Section: Structural Organization Of Its Chromatin During Meiosismentioning

confidence: 99%

Chromatin Organization and Remodeling of Interstitial Telomeric Sites During Meiosis in the Mongolian Gerbil (Meriones unguiculatus)

et al. 2014

View full text Add to dashboard Cite

Telomeric DNA repeats are key features of chromosomes that allow the maintenance of integrity and stability in the telomeres. However, interstitial telomere sites (ITSs) can also be found along the chromosomes, especially near the centromere, where they may appear following chromosomal rearrangements like Robertsonian translocations. There is no defined role for ITSs, but they are linked to DNA damage-prone sites. We were interested in studying the structural organization of ITSs during meiosis, a kind of cell division in which programmed DNA damage events and noticeable chromatin reorganizations occur. Here we describe the presence of highly amplified ITSs in the pericentromeric region of Mongolian gerbil (Meriones unguiculatus) chromosomes. During meiosis, ITSs show a different chromatin conformation than DNA repeats at telomeres, appearing more extended and accumulating heterochromatin markers. Interestingly, ITSs also recruit the telomeric proteins RAP1 and TRF1, but in a stage-dependent manner, appearing mainly at late prophase I stages. We did not find a specific accumulation of DNA repair factors to the ITSs, such as gH2AX or RAD51 at these stages, but we could detect the presence of MLH1, a marker for reciprocal recombination. However, contrary to previous reports, we did not find a specific accumulation of crossovers at ITSs. Intriguingly, some centromeric regions of metacentric chromosomes may bind the nuclear envelope through the association to SUN1 protein, a feature usually performed by telomeres. Therefore, ITSs present a particular and dynamic chromatin configuration in meiosis, which could be involved in maintaining their genetic stability, but they additionally retain some features of distal telomeres, provided by their capability to associate to telomere-binding proteins.

show abstract

“…In meiotic cells, the error-prone NHEJ is suppressed, which is probably due to loss of expression of Ku70, the key protein for NHEJ. 7,8 The error-free HR is used for repair of SPO11-induced DSBs. HR uses an intact copy of DNA as the template for the high fidelity repair, which avoids generation of genetic mutations during DSB repair in meiotic cells.…”

Section: Crossovers Are Generated During Meiotic Prophasementioning

confidence: 99%

Double-strand break repair on sex chromosomes: challenges during male meiotic prophase

Lü

2015

Cell Cycle

View full text Add to dashboard Cite

Genetic probing of homologous recombination and non-homologous end joining during meiotic prophase in irradiated mouse spermatocytes

Cited by 39 publications

References 35 publications

Ku70 and non-homologous end joining protect testicular cells from DNA damage

Ku70 and non-homologous end joining protect testicular cells from DNA damage

Chromatin Organization and Remodeling of Interstitial Telomeric Sites During Meiosis in the Mongolian Gerbil (Meriones unguiculatus)

Double-strand break repair on sex chromosomes: challenges during male meiotic prophase

Contact Info

Product

Resources

About