Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China.
Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Reprod Sci. 2021 Oct;28(10):2942-2950. doi: 10.1007/s43032-021-00633-z. Epub 2021 Jun 23.
Tubulin beta 8 class VIII (TUBB8) is a special β-tubulin isotype that mainly expressed in primate oocytes and early embryos and identified as the disease-causing gene of human oocyte maturation arrest. To identify the disease-causing genes in 2 patients with female infertility due to large polar body oocyte or fertilization failure, whole-exome sequencing was performed on the patients and available family members. We identified a novel heterozygous missense mutation c.817C>G (p.L273V) and a recently reported heterozygous missense mutation c.608A>G (p.D203G) in TUBB8 from two patients, respectively. We found oocyte with a large polar body in the patient who carried the p.D203G mutation in TUBB8. Bioinformatics analysis showed that these two mutations are harmful. The results of western blot and RT-PCR experiments showed that the D203G mutation caused a significant decrease in the expression of TUBB8, and immunostaining showed that the TUBB8 mutation caused abnormal microtubule morphology. These findings suggest that TUBB8 mutations resulted in oocyte with a large polar body and fertilization failure in patients.
微管蛋白β 8 类 VIII （TUBB8）是一种特殊的β-微管蛋白同工型，主要在灵长类卵母细胞和早期胚胎中表达，并被鉴定为人类卵母细胞成熟阻滞的致病基因。为了鉴定 2 名因大极体卵母细胞或受精失败导致女性不育的患者的致病基因，对患者及其可利用的家庭成员进行了全外显子组测序。我们分别在两名患者中鉴定出 TUBB8 中的一个新型杂合错义突变 c.817C>G（p.L273V）和一个最近报道的杂合错义突变 c.608A>G（p.D203G）。我们发现携带 TUBB8 中 p.D203G 突变的患者的卵母细胞有大极体。生物信息学分析表明这两种突变均具有危害性。Western blot 和 RT-PCR 实验结果表明，D203G 突变导致 TUBB8 的表达显著下降，免疫染色显示 TUBB8 突变导致微管形态异常。这些发现表明 TUBB8 突变导致患者的卵母细胞有大极体和受精失败。
