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.
|Keywords||Animals, Centrosome/metabolism/ultrastructure, Endosomes/metabolism/ultrastructure, Fluorescent Antibody Technique/methods, Gene Expression Regulation, Developmental/*physiology, Homozygote, Male, Mice, Mice, Knockout, Microtubule-Associated Proteins/genetics/*metabolism, Microtubules/metabolism/ultrastructure, Neoplasm Proteins/genetics/*metabolism, Protein Transport, Sperm Head/metabolism/ultrastructure, Spermatids/*metabolism/ultrastructure, Spermatogenesis/*physiology|
|Persistent URL||dx.doi.org/10.1101/gad.344505, hdl.handle.net/1765/13948|
Akhmanova, A., Mausset-Bonnefont, A.L., van Cappellen, W.A., Keijzer, N., Hoogenraad, C.C., Stepanova, T., … Galjart, N.J.. (2005). The microtubule plus-end-tracking protein CLIP-170 associates with the spermatid manchette and is essential for spermatogenesis.. Genes & Development, 19(20), 2501–2515. doi:10.1101/gad.344505