{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T04:57:58Z","timestamp":1781672278242,"version":"3.54.5"},"reference-count":35,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T00:00:00Z","timestamp":1781654400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec>\n                    <jats:title>Backgrounds<\/jats:title>\n                    <jats:p>\n                      Pediatric-onset primary ovarian insufficiency (POI) presents distinct clinical challenges, including delayed puberty or growth retardation. Previously, we reported a Chinese family with POI harboring compound heterozygous variants (p.C242R and p.S445*) in\n                      <jats:italic>MCM8<\/jats:italic>\n                      gene, a critical factor for DNA repair and gonadal homeostasis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>\n                      This study describes clinical findings of pediatric-onset POI patients with compound heterozygous\n                      <jats:italic>MCM8<\/jats:italic>\n                      variants and investigates the\n                      <jats:italic>in vitro<\/jats:italic>\n                      functional consequences of an artificial double-mutant MCM8 construct harboring both p.C242R and p.S445*. Using this overexpression model, we assessed DNA damage response, protein interactions, and transcriptomic changes associated with the double-mutant MCM8.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>HeLa cell models were used to overexpress double-mutant (p.C242R and p.S445*) or wild-type MCM8. Functional consequences were evaluated using immunofluorescence staining, flow cytometry, and western blotting to assess DNA damage repair, cell cycle and apoptosis. Co-immunoprecipitation coupled with mass spectrometry (CoIP\u2013MS\/MS) was used to screen the disrupted protein interactome. Cut&amp;amp;Tag and mRNA-seq analyses were used to examine chromatin-binding-associated changes and transcriptomic alterations.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Ovarian tissues from POI patients exhibited reduced MCM8 expression and increased apoptosis. Cells expressing the artificial double-mutant MCM8 construct showed delayed resolution of DNA damage, as indicated by persistent \u03b3-H2AX accumulation, and altered recruitment of DMC1 and RAD51. These changes were accompanied by S-phase accumulation and increased apoptosis. CoIP\u2013MS\/MS analysis identified altered interaction between double-mutant MCM8 and MCM6, suggesting possible changes in replication-associated protein interactions. Integrated CUT&amp;amp;Tag and RNA-seq analyses identified MCM8-associated chromatin-binding changes and transcriptomic alterations involving candidate genes enriched in ovarian survival and metabolic pathways, including the PI3K\/AKT signaling pathway.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>\n                      These specific\n                      <jats:italic>MCM8<\/jats:italic>\n                      variants are clinically associated with pediatric-onset POI.\n                      <jats:italic>In vitro<\/jats:italic>\n                      , expression of double-mutant MCM8 construct was associated with impaired DNA damage resolution, altered MCM8-associated protein interactions, transcriptomic alterations, cell-cycle disturbance, and increased apoptosis. These findings provide cellular observations that may help generate hypotheses regarding how MCM8 dysfunction could contribute to ovarian insufficiency.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fendo.2026.1807887","type":"journal-article","created":{"date-parts":[[2026,6,17]],"date-time":"2026-06-17T04:50:59Z","timestamp":1781671859000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["MCM8 variants in two patients with primary ovarian insufficiency: clinical findings and in vitro defective DNA repair revealed by an MCM8 double-mutant construct"],"prefix":"10.3389","volume":"17","author":[{"given":"Fei","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Endocrinology, Shanghai Children\u2019s Hospital, School of Medicine, Shanghai Jiao Tong University","place":["Shanghai, 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