Axonemal doublet microtubules can split into two complete singlets in human sperm flagellum tips.

Zabeo D, Croft JT, Höög JL

FEBS Lett. 593 (9) 892-902 [2019-05-00; online 2019-04-19]

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.

Cryo-EM [Service]

PubMed 30959570

DOI 10.1002/1873-3468.13379

Crossref 10.1002/1873-3468.13379

pmc: PMC6594080

Publications 9.5.0