Mutation in CATIP (C2orf62) causes oligoteratoasthenozoospermia by affecting actin dynamics
Mutation in CATIP (C2orf62) causes oligoteratoasthenozoospermia by affecting actin dynamics
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DOI：
10.1136/jmedgenet-2019-106825
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发表时间：
2021-02-01
影响因子：
4
通讯作者：
Parvari, Ruti
中科院分区：
文献类型：
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作者：
Arafat, Maram;Harlev, Avi;Parvari, Ruti
背景少精子症(OTA)结合了精子数量、形态和运动能力的恶化，导致男性因素不育。方法我们利用全基因组基因分型和外显子组测序，在贝都因血亲家庭的四名男性中鉴定出导致OTA的突变。我们通过用 pCDNA3.1 质粒构建体转染来表达在羧基末端标有 c-Myc 的正常和突变蛋白，以评估对 HEK293 细胞中蛋白稳定性的影响以及对视网膜色素上皮细胞中肌动蛋白再聚合动力学的影响。通过透射电子显微镜观察患者的精子样本以确定轴丝结构，并用荧光鬼笔环肽染色以观察原纤维（F）-肌动蛋白。 结果纤毛发生相关TTC17相互作用蛋白（CATIP）中的纯合错义突变：c。 T103A，p。 Phe35Ile 是一种编码对肌动蛋白组织和纤毛发生很重要的蛋白质的基因，被确定为致病突变，LOD 评分为 3.25。与正常蛋白质相比，突变降低了蛋白质的稳定性。此外，正常蛋白而非突变蛋白的过度表达会抑制用细胞松弛素 D 破坏后肌动蛋白的再聚合。患者精子轴丝的比例很高，并且 F-肌动蛋白分布紊乱。结论这是人类 CATIP 隐性突变的第一份报告。所鉴定的突变可能通过参与肌动蛋白聚合和肌动蛋白细胞骨架而导致弱精子症。据报道，小鼠 CATIP 敲除纯合子表明男性不育是唯一的表型。
BackgroundOligoteratoasthenozoospermia (OTA) combines deteriorated quantity, morphology and motility of the sperm, resulting in male factor infertility.MethodsWe used whole genome genotyping and exome sequencing to identify the mutation causing OTA in four men in a consanguineous Bedouin family. We expressed the normal and mutated proteins tagged with c-Myc at the carboxy termini by transfection with pCDNA3.1 plasmid constructs to evaluate the effects on protein stability in HEK293 cells and on the kinetics of actin repolymerisation in retinal pigment epithelium cells. Patients' sperm samples were visualised by transmission electron microscopy to determine axoneme structures and were stained with fluorescent phalloidin to visualise the fibrillar (F)-actin.ResultsA homozygous missense mutation in Ciliogenesis Associated TTC17 Interacting Protein (CATIP): c. T103A, p. Phe35Ile, a gene encoding a protein important in actin organisation and ciliogenesis, was identified as the causative mutation with a LOD score of 3.25. The mutation reduces the protein stability compared with the normal protein. Furthermore, overexpression of the normal protein, but not the mutated protein, inhibits repolymerisation of actin after disruption with cytochalasin D. A high percentage of spermatozoa axonemes from patients have abnormalities, as well as disturbances in the distribution of F-actin.ConclusionThis is the first report of a recessive mutation in CATIP in humans. The identified mutation may contribute to asthenozoospermia by its involvement in actin polymerisation and on the actin cytoskeleton. A mouse knockout homozygote for CATIP was reported to demonstrate male infertility as the sole phenotype.