{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n HUS1B is a paralog of the canonical checkpoint gene HUS1 that encodes a protein sharing substantial similarity yet exhibiting distinct biochemical interactions and functions. Unlike HUS1, which forms part of the RAD9–RAD1–HUS1 (9–1–1) complex by binding RAD9, RAD1, and itself, HUS1B selectively interacts with RAD1 but not with RAD9 or HUS1. This unique binding profile indicates that HUS1B cannot simply substitute for HUS1 in the conventional 9–1–1 clamp but may instead participate in alternative checkpoint complexes, particularly in tissues such as the testis where its expression parallels that of HUS1 and where alternative clamps have been implicated in meiotic double‐strand break repair and genome maintenance."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In addition to its proposed role in cell cycle checkpoint regulation and DNA repair, aberrant regulation of HUS1B has been linked to clinical conditions. Hypomethylation of its promoter alters HUS1B expression in placental tissues, suggesting a contribution to placental function and a potential impact on fetal growth and low birth weight outcomes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": " Moreover, a functional variant within HUS1B (rs61748571 A>G) has been associated with differences in platinum-based chemotherapy response in epithelial ovarian cancer patients, underscoring its clinical relevance as a possible biomarker for treatment outcomes."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Collectively, these findings support a model in which HUS1B plays distinct yet related roles in regulating cell cycle checkpoints and preserving genomic integrity. Its involvement in alternative 9–1–1 complexes may be particularly important in specialized cellular contexts such as meiosis, while its dysregulation—whether by altered epigenetic modifications or genetic variation—can have significant pathological consequences.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Haiying Hang, Yuzhu Zhang, Roland L Dunbrack, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "Identification and characterization of RAD9B, a paralog of the RAD9 checkpoint gene."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Genomics (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/s0888-7543(03)00200-3"}], "href": "https://doi.org/10.1016/s0888-7543(03"}, {"type": "t", "text": "00200-3) PMID: "}, {"type": "a", "children": [{"type": "t", "text": "14611806"}], "href": "https://pubmed.ncbi.nlm.nih.gov/14611806"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Janette Mareska Rumbajan, Yuko Yamaguchi, Kazuhiko Nakabayashi, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The HUS1B promoter is hypomethylated in the placentas of low-birth-weight infants."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Gene (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.gene.2016.02.025"}], "href": "https://doi.org/10.1016/j.gene.2016.02.025"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26911255"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26911255"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Haoran Li, Hongji Dai, Tingyan Shi, et al. 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