Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
FEBS Lett. 2019 May;593(9):892-902. doi: 10.1002/1873-3468.13379. Epub 2019 Apr 19.
Motile flagella are crucial for human fertility and embryonic development. The distal tip of the flagellum is where growth and intra-flagellar transport are coordinated. In most model organisms, but not all, the distal tip includes a 'singlet region', where axonemal doublet microtubules (dMT) terminate and only complete A-tubules extend as singlet microtubules (sMT) to the tip. How a human flagellar tip is structured is unknown. Here, the flagellar tip structure of human spermatozoa was investigated by cryo-electron tomography, revealing the formation of a complete sMT from both the A-tubule and B-tubule of dMTs. This different tip arrangement in human spermatozoa shows the need to investigate human flagella directly in order to understand their role in health and disease.
运动性鞭毛对于人类的生育能力和胚胎发育至关重要。鞭毛的远侧末端是生长和鞭毛内运输协调的地方。在大多数模式生物中，但不是全部，远侧末端包括一个“单体区域”，在这里轴丝二联微管（dMT）终止，只有完整的 A 微管延伸为单体微管（sMT）到达末端。人类鞭毛末端的结构尚不清楚。在这里，通过冷冻电子断层扫描研究了人类精子的鞭毛末端结构，揭示了从 dMT 的 A 微管和 B 微管形成完整的 sMT。人类精子中这种不同的末端排列表明，需要直接研究人类鞭毛，以便了解它们在健康和疾病中的作用。
