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Deletion of genes implicated in protecting the integrity of male germ cells has differential effects on the incidence of DNA breaks and germ cell loss.

Paul C, Povey JE, Lawrence NJ, Selfridge J, Melton DW, Saunders PT - PLoS ONE (2007)

Bottom Line: We demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells.These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production.These findings increase our understanding of the ways in which gene mutations can have an impact on male fertility.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Human Reproductive Sciences Unit, Queen's Medical Research Institute, Edinburgh, United Kingdom.

ABSTRACT

Background: Infertility affects approximately 20% of couples in Europe and in 50% of cases the problem lies with the male partner. The impact of damaged DNA originating in the male germ line on infertility is poorly understood but may increase miscarriage. Mouse models allow us to investigate how deficiencies in DNA repair/damage response pathways impact on formation and function of male germ cells. We have investigated mice with deletions of ERCC1 (excision repair cross-complementing gene 1), MSH2 (MutS homolog 2, involved in mismatch repair pathway), and p53 (tumour suppressor gene implicated in elimination of germ cells with DNA damage).

Principal findings: We demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells. Sertoli cell-only tubules were detected in testes from mice lacking expression of ERCC1 or MSH2 but not p53. The number of sperm recovered from epididymes was significantly reduced in mice lacking testicular ERCC1 and 40% of sperm contained DNA breaks whereas the numbers of sperm were not different to controls in adult Msh2 -/- or p53 -/- mice nor did they have significantly compromised DNA.

Conclusions: These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production. These findings increase our understanding of the ways in which gene mutations can have an impact on male fertility.

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Quantification of caspase-3 positive germ cells.The total number of caspase 3 positive cells was determined in 4 sections from each mouse. An * (P<0.05) indicates significant variation compared with wild type littermates. For TG-Ercc1 data n = 5, for Msh2 and p53 data n = 3.
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pone-0000989-g002: Quantification of caspase-3 positive germ cells.The total number of caspase 3 positive cells was determined in 4 sections from each mouse. An * (P<0.05) indicates significant variation compared with wild type littermates. For TG-Ercc1 data n = 5, for Msh2 and p53 data n = 3.

Mentions: Testicular sections were stained for cleaved caspase-3 to detect any cells that were undergoing apoptosis. In testes from TG-Ercc1 −/− mice a 3.5 fold increase in apoptotic germ cells was observed compared to controls (Figure 2A). A similar increase was evident in the p53 −/− mice (Figure 2D). The majority of cells in these mutants undergoing apoptosis appeared to be spermatogonia or secondary spermatocytes and most occurred at stage XII of spermatogenesis. No increase in caspase 3-positive cells was observed in the Msh2 −/− adults. In order to determine whether an earlier wave of apoptosis might account for the presence of SCO tubules in the adult Msh2 −/− testes, testes from mice during the first wave of spermatogenesis (day 30) were also examined and in these a slight but non-significant increase in the number of caspase-3 positive germ cells was detected (Figure 2C).


Deletion of genes implicated in protecting the integrity of male germ cells has differential effects on the incidence of DNA breaks and germ cell loss.

Paul C, Povey JE, Lawrence NJ, Selfridge J, Melton DW, Saunders PT - PLoS ONE (2007)

Quantification of caspase-3 positive germ cells.The total number of caspase 3 positive cells was determined in 4 sections from each mouse. An * (P<0.05) indicates significant variation compared with wild type littermates. For TG-Ercc1 data n = 5, for Msh2 and p53 data n = 3.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1991594&req=5

pone-0000989-g002: Quantification of caspase-3 positive germ cells.The total number of caspase 3 positive cells was determined in 4 sections from each mouse. An * (P<0.05) indicates significant variation compared with wild type littermates. For TG-Ercc1 data n = 5, for Msh2 and p53 data n = 3.
Mentions: Testicular sections were stained for cleaved caspase-3 to detect any cells that were undergoing apoptosis. In testes from TG-Ercc1 −/− mice a 3.5 fold increase in apoptotic germ cells was observed compared to controls (Figure 2A). A similar increase was evident in the p53 −/− mice (Figure 2D). The majority of cells in these mutants undergoing apoptosis appeared to be spermatogonia or secondary spermatocytes and most occurred at stage XII of spermatogenesis. No increase in caspase 3-positive cells was observed in the Msh2 −/− adults. In order to determine whether an earlier wave of apoptosis might account for the presence of SCO tubules in the adult Msh2 −/− testes, testes from mice during the first wave of spermatogenesis (day 30) were also examined and in these a slight but non-significant increase in the number of caspase-3 positive germ cells was detected (Figure 2C).

Bottom Line: We demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells.These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production.These findings increase our understanding of the ways in which gene mutations can have an impact on male fertility.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Human Reproductive Sciences Unit, Queen's Medical Research Institute, Edinburgh, United Kingdom.

ABSTRACT

Background: Infertility affects approximately 20% of couples in Europe and in 50% of cases the problem lies with the male partner. The impact of damaged DNA originating in the male germ line on infertility is poorly understood but may increase miscarriage. Mouse models allow us to investigate how deficiencies in DNA repair/damage response pathways impact on formation and function of male germ cells. We have investigated mice with deletions of ERCC1 (excision repair cross-complementing gene 1), MSH2 (MutS homolog 2, involved in mismatch repair pathway), and p53 (tumour suppressor gene implicated in elimination of germ cells with DNA damage).

Principal findings: We demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells. Sertoli cell-only tubules were detected in testes from mice lacking expression of ERCC1 or MSH2 but not p53. The number of sperm recovered from epididymes was significantly reduced in mice lacking testicular ERCC1 and 40% of sperm contained DNA breaks whereas the numbers of sperm were not different to controls in adult Msh2 -/- or p53 -/- mice nor did they have significantly compromised DNA.

Conclusions: These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production. These findings increase our understanding of the ways in which gene mutations can have an impact on male fertility.

Show MeSH
Related in: MedlinePlus