Unscheduled DNA synthesis assay in mammalian spermatogenic cells: An update

Indirect mechanisms of radiation induced genomic instability at repeat loci

“…Although the early and late spermatid stages are both post-meiotic, and lack DNA replication, these two stages differ in their DNA damage repair capacity. The round and early elongating spermatid stage is known to exhibit unscheduled DNA synthesis when challenged by X-rays, UV and a variety of chemical mutagens; this activity is lost in the late spermatid stage [42]. The difference may affect the induction of ESTR mutation.…”

Indirect mechanisms of radiation induced genomic instability at repeat loci

“…Although the early and late spermatid stages are both post-meiotic, and lack DNA replication, these two stages differ in their DNA damage repair capacity. The round and early elongating spermatid stage is known to exhibit unscheduled DNA synthesis when challenged by X-rays, UV and a variety of chemical mutagens; this activity is lost in the late spermatid stage [42]. The difference may affect the induction of ESTR mutation.…”

Changes in spermatozoal chromatin packaging and susceptibility to oxidative challenge during aging

“…The increased chromatin dissociation after H 2 O 2 treatment is most likely due to oxidant-induced DNA breaks. Owing to the condensed nature of the chromatin and the loss of most of their cytoplasm, mature spermatozoa lack appreciable levels of DNA repair (65)(66)(67). Knowing that OH • damages DNA by inducing base modification and strand breaks (41), we used the quantitative PCR assay to examine if the slight difference in percentage of abnormal DD that we saw between young and old animals was indeed due to increased susceptibility to oxidative DNA modifications with age.…”

Mechanisms and consequences of paternally‐transmitted chromosomal abnormalities

“…To date, no mutagen has induced transmissible chromosomal defects in stem cell spermatogonia and very few have induced transmissible gene mutations in these cells (Shelby, 1996). As mentioned earlier, the high sensitivity of postmeiotic cells is probably related to the reduced DNA repair capacity of late spermatids and sperm, when compared with early spermatids and the other spermatogenic cell types (Sega, 1979; Sotomayor and Sega, 2000).…”

Indirect mechanisms of radiation induced genomic instability at repeat loci

“…Although the early and late spermatid stages are both post-meiotic, and lack DNA replication, these two stages differ in their DNA damage repair capacity. The round and early elongating spermatid stage is known to exhibit unscheduled DNA synthesis when challenged by X-rays, UV and a variety of chemical mutagens; this activity is lost in the late spermatid stage [42]. The difference may affect the induction of ESTR mutation.…”

Changes in spermatozoal chromatin packaging and susceptibility to oxidative challenge during aging

“…The increased chromatin dissociation after H 2 O 2 treatment is most likely due to oxidant-induced DNA breaks. Owing to the condensed nature of the chromatin and the loss of most of their cytoplasm, mature spermatozoa lack appreciable levels of DNA repair (65)(66)(67). Knowing that OH • damages DNA by inducing base modification and strand breaks (41), we used the quantitative PCR assay to examine if the slight difference in percentage of abnormal DD that we saw between young and old animals was indeed due to increased susceptibility to oxidative DNA modifications with age.…”

Mechanisms and consequences of paternally‐transmitted chromosomal abnormalities

“…To date, no mutagen has induced transmissible chromosomal defects in stem cell spermatogonia and very few have induced transmissible gene mutations in these cells (Shelby, 1996). As mentioned earlier, the high sensitivity of postmeiotic cells is probably related to the reduced DNA repair capacity of late spermatids and sperm, when compared with early spermatids and the other spermatogenic cell types (Sega, 1979; Sotomayor and Sega, 2000).…”

Indirect mechanisms of radiation induced genomic instability at repeat loci

“…Although the early and late spermatid stages are both post-meiotic, and lack DNA replication, these two stages differ in their DNA damage repair capacity. The round and early elongating spermatid stage is known to exhibit unscheduled DNA synthesis when challenged by X-rays, UV and a variety of chemical mutagens; this activity is lost in the late spermatid stage [42]. The difference may affect the induction of ESTR mutation.…”

Changes in spermatozoal chromatin packaging and susceptibility to oxidative challenge during aging

“…The increased chromatin dissociation after H 2 O 2 treatment is most likely due to oxidant-induced DNA breaks. Owing to the condensed nature of the chromatin and the loss of most of their cytoplasm, mature spermatozoa lack appreciable levels of DNA repair (65)(66)(67). Knowing that OH • damages DNA by inducing base modification and strand breaks (41), we used the quantitative PCR assay to examine if the slight difference in percentage of abnormal DD that we saw between young and old animals was indeed due to increased susceptibility to oxidative DNA modifications with age.…”

Mechanisms and consequences of paternally‐transmitted chromosomal abnormalities

“…To date, no mutagen has induced transmissible chromosomal defects in stem cell spermatogonia and very few have induced transmissible gene mutations in these cells (Shelby, 1996). As mentioned earlier, the high sensitivity of postmeiotic cells is probably related to the reduced DNA repair capacity of late spermatids and sperm, when compared with early spermatids and the other spermatogenic cell types (Sega, 1979; Sotomayor and Sega, 2000).…”