| First Author | Chicheportiche A | Year | 2007 |
| Journal | J Cell Sci | Volume | 120 |
| Issue | Pt 10 | Pages | 1733-42 |
| PubMed ID | 17456548 | Mgi Jnum | J:124198 |
| Mgi Id | MGI:3721023 | Doi | 10.1242/jcs.004945 |
| Citation | Chicheportiche A, et al. (2007) Characterization of Spo11-dependent and independent phospho-H2AX foci during meiotic prophase I in the male mouse. J Cell Sci 120(Pt 10):1733-42 |
| abstractText | Meiotic DNA double strand breaks (DSBs) are indicated at leptotene by the phosphorylated form of histone H2AX (gamma-H2AX). In contrast to previous studies, we identified on both zygotene and pachytene chromosomes two distinct types of gamma-H2AX foci: multiple small (S) foci located along autosomal synaptonemal complexes (SCs) and larger signals on chromatin loops (L-foci). The S-foci number gradually declined throughout pachytene, in parallel with the repair of DSBs monitored by repair proteins suggesting that S-foci mark DSB repair events. We validated this interpretation by showing the absence of S-foci in Spo11(-/-) spermatocytes. By contrast, the L-foci number was very low through pachytene. Based on the analysis of gamma-H2AX labeling after irradiation of spermatocytes, the formation of DSBs clearly induced L-foci formation. Upon DSB repair, these foci appear to be processed and lead to the above mentioned S-foci. The presence of L-foci in wild-type pachytene and diplotene could therefore reflect delayed or unregulated DSB repair events. Interestingly, their distribution was different in Spo11(+/-) spermatocytes compared with Spo11(+/+) spermatocytes, where DSB repair might be differently regulated as a response to homeostatic control of crossing-over. The presence of these L-foci in Spo11(-/-) spermatocytes raises the interesting possibility of yet uncharacterized alterations in DNA or chromosome structure in Spo11(-/-) cells. |
