The microtubule plus-end-tracking protein CLIP-170 associates with the spermatid manchette and is essential for spermatogenesis.
CLIP-170 is a microtubule "plus-end-tracking protein" implicated in the control of microtubule dynamics, dynactin localization, and the linking of endosomes to microtubules. To investigate the function of mouse CLIP-170, we generated CLIP-170 knockout and GFP-CLIP-170 knock-in alleles. Residual CLIP-170 is detected in lungs and embryos of homozygous CLIP-170 knockout mice, but not in other tissues and cell types, indicating that we have generated a hypomorphic mutant. Homozygous CLIP-170 knockout mice are viable and appear normal. However, male knockout mice are subfertile and produce sperm with abnormal heads. Using the knock-in mice, we followed GFP-CLIP-170 expression and behavior in dissected, live testis tubules. We detect plus-end-tracking GFP-CLIP-170 in spermatogonia. As spermatogenesis proceeds, GFP-CLIP-170 expression increases and the fusion protein strongly marks syncytia of differentiated spermatogonia and early prophase spermatocytes. Subsequently GFP-CLIP-170 levels drop, but during spermiogenesis (post-meiotic development), GFP-CLIP-170 accumulates again and is present on spermatid manchettes and centrosomes. Bleaching studies show that, as spermatogenesis progresses, GFP-CLIP-170 converts from a mobile plus-end-tracking protein to a relatively immobile protein. We propose that CLIP-170 has a structural function in the male germline, in particular in spermatid differentiation and sperm head shaping.
Akhmanova
Anna
A
Department of Cell Biology and Genetics, Erasmus MC, 3000 DR Rotterdam, The Netherlands.
Mausset-Bonnefont
Anne-Laure
AL
van Cappellen
Wiggert
W
Keijzer
Nanda
N
Hoogenraad
Casper C
CC
Stepanova
Tatiana
T
Drabek
Ksenija
K
van der Wees
Jacqueline
J
Mommaas
Mieke
M
Onderwater
Jos
J
van der Meulen
Hans
H
Tanenbaum
Marvin E
ME
Medema
Rene H
RH
Hoogerbrugge
Jos
J
Vreeburg
Jan
J
Uringa
Evert-Jan
EJ
Grootegoed
J Anton
JA
Grosveld
Frank
F
Galjart
Niels
N
D000818:Animals; D018385:Centrosome / Q000378:metabolism / Q000648:ultrastructure; D011992:Endosomes / Q000378:metabolism / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique / Q000379:methods; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006720:Homozygote; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D013077:Sperm Head / Q000378:metabolism / Q000648:ultrastructure; D013087:Spermatids / Q000378:metabolism* / Q000648:ultrastructure; D013091:Spermatogenesis / Q000502:physiology*
D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; C076744:cytoplasmic linker protein 170