Increased chromosomal instability impairs oocyte quality,contributing to female reproductive aging.The telomeric DNA damage response(DDR)is essential for genomic stability;however,how oocytes respond to telomeric dama...Increased chromosomal instability impairs oocyte quality,contributing to female reproductive aging.The telomeric DNA damage response(DDR)is essential for genomic stability;however,how oocytes respond to telomeric damage remains elusive.Here,we observed that aged human germinal vesicle(GV)oocytes accumulated telomeric DNA damage.We next established a telomeric DNA damage model with CRISPR/Cas9 in mouse oocytes,which exhibited increased chromosome instability and impaired meiotic maturation.Furthermore,telomeric DNA damage in oocytes did not initiate telomere fusion but rather accelerated telomere movement and triggered break-induced telomere synthesis(BITS).Mechanistically,RPA32 and RAD51 were recruited to damaged telomeres,and contributed to BITS along with ATR and PARP1.However,telomeric DNA damage recruited few RNF8 in fully grown oocytes,possibly impeding the 53BP1 recruitment.Despite minimal changes in the overall activity of RAD51-promoted DNA repair in GV oocytes with maternal age,this DDR machinery was preferentially involved in non-telomeric regions in aged oocytes.Consequently,upon encountering telomeric DNA damage,aged oocytes might undergo insufficient telomeric DDR and BITS.Together,our study illustrates that telomeric DDR recruits key factors,such as RAD51,to activate BITS,and that insufficient telomeric DDR increases chromosomal instabilityinagedoocytes.展开更多
Parthenogenetic embryos,created by activation and diploidization of oocytes,arrest at mid-gestation for defective paternal imprints,which impair placental development.Also,viable offspring has not been obtained withou...Parthenogenetic embryos,created by activation and diploidization of oocytes,arrest at mid-gestation for defective paternal imprints,which impair placental development.Also,viable offspring has not been obtained without genetic manipulation from parthenogenetic embryonic stem cells(pESCs)derived from parthenogenetic embryos,presumably attributable to their aberrant imprinting.We show that an unlimited number of oocytes can be derived from pESCs and produce healthy offspring.Moreover,normal expression of imprinted genes is found in the germ cells and the mice.pESCs exhibited imprinting consistent with exclusively maternal lineage,and higher X-chromosome activation compared to female ESCs derived from the same mouse genetic background.pESCs differentiated into primordial germ cell-like cells(PGCLCs)and formed oocytes following in vivo transplantation into kidney capsule that produced fertile pups and reconstituted ovarian endocrine function.The transcriptome and methylation of imprinted and X-linked genes in pESC-PGCLCs closely resembled those of in vivo produced PGCs,consistent with efficient reprogramming of methylation and genomic imprinting.These results demonstrate that amplification of germ cells through parthenogenesis faithfully maintains maternal imprinting,offering a promising route for deriving functional oocytes and having potential in rebuilding ovarian endocrine function.展开更多
基金supported by the National Natural Science Foundation of China(82271688 and 82201827)the Guangdong Basic and Applied Basic Research Foundation(2023A1515111005)+1 种基金Fundamental Research Funds for the Central Universities,Sun Yat-sen University(24qnpy077)the Guangdong Province Excellent Youth Team Project(2024B1515040009).
文摘Increased chromosomal instability impairs oocyte quality,contributing to female reproductive aging.The telomeric DNA damage response(DDR)is essential for genomic stability;however,how oocytes respond to telomeric damage remains elusive.Here,we observed that aged human germinal vesicle(GV)oocytes accumulated telomeric DNA damage.We next established a telomeric DNA damage model with CRISPR/Cas9 in mouse oocytes,which exhibited increased chromosome instability and impaired meiotic maturation.Furthermore,telomeric DNA damage in oocytes did not initiate telomere fusion but rather accelerated telomere movement and triggered break-induced telomere synthesis(BITS).Mechanistically,RPA32 and RAD51 were recruited to damaged telomeres,and contributed to BITS along with ATR and PARP1.However,telomeric DNA damage recruited few RNF8 in fully grown oocytes,possibly impeding the 53BP1 recruitment.Despite minimal changes in the overall activity of RAD51-promoted DNA repair in GV oocytes with maternal age,this DDR machinery was preferentially involved in non-telomeric regions in aged oocytes.Consequently,upon encountering telomeric DNA damage,aged oocytes might undergo insufficient telomeric DDR and BITS.Together,our study illustrates that telomeric DDR recruits key factors,such as RAD51,to activate BITS,and that insufficient telomeric DDR increases chromosomal instabilityinagedoocytes.
基金This work was supported by China National Key R&D Program(2018YFC1003004,2018YFA0107002)the National Natural Science Foundation of China(31430052,91749129)as well as the Stanley H.Kaplan Research Fund at NYU School of Medicine.
文摘Parthenogenetic embryos,created by activation and diploidization of oocytes,arrest at mid-gestation for defective paternal imprints,which impair placental development.Also,viable offspring has not been obtained without genetic manipulation from parthenogenetic embryonic stem cells(pESCs)derived from parthenogenetic embryos,presumably attributable to their aberrant imprinting.We show that an unlimited number of oocytes can be derived from pESCs and produce healthy offspring.Moreover,normal expression of imprinted genes is found in the germ cells and the mice.pESCs exhibited imprinting consistent with exclusively maternal lineage,and higher X-chromosome activation compared to female ESCs derived from the same mouse genetic background.pESCs differentiated into primordial germ cell-like cells(PGCLCs)and formed oocytes following in vivo transplantation into kidney capsule that produced fertile pups and reconstituted ovarian endocrine function.The transcriptome and methylation of imprinted and X-linked genes in pESC-PGCLCs closely resembled those of in vivo produced PGCs,consistent with efficient reprogramming of methylation and genomic imprinting.These results demonstrate that amplification of germ cells through parthenogenesis faithfully maintains maternal imprinting,offering a promising route for deriving functional oocytes and having potential in rebuilding ovarian endocrine function.
