Identification of novel Prominin-1/CD133 splice variants with alternative C-termini and their expression in epididymis and testis.
Prominin-1/CD133 is a five-membrane-span glycoprotein that is thought to act as an organizer of plasma-membrane protrusions. Here, we report the molecular and cell-biological characterization of four novel prominin-1 splice variants isolated from a mouse testis cDNA library and referred to as prominin-1.s3 to prominin-1.s6. Compared with kidney-derived prominin-1.s1, the s3, s4 and s5 variants contain a distinct cytoplasmic C-terminal domain. The s4 and s5 variants bear, in addition, two and one inframe deletion(s), respectively, in the extracellular domains. The s6 variant displays a truncated C-terminal domain caused by a premature termination resulting from intron retention. Upon their ectopic expression in Chinese hamster ovary cells, the s3 and s6 variants were found to be concentrated in plasma-membrane protrusions, whereas the s4 and s5 variants did not reach the cell surface. Biochemical analyses suggest that most of the prominin-1 in the adult male reproductive system is expressed as the s6 variant. Immunohistological and electron microscopic analyses show that prominin-1 is: (1) confined to the apical surface of the epithelium all along the epididymal duct, with the exception of the initial segment; (2) concentrated in stereocilia of the epididymal duct epithelium; and (3) found on the tail of developing spermatozoa in seminiferous tubules. Our data suggest that prominin-1 is involved in the formation and/or stabilization of epididymal stereocilia and the tail of spermatozoa, and hence might play a dual role in the biogenesis of spermatozoa.
Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
Christine A
CA
Fargeas
Angret
A
Joester
Ewa
E
Missol-Kolka
Andrea
A
Hellwig
Wieland B
WB
Huttner
Denis
D
Corbeil
D000071916:AC133 Antigen; D017398:Alternative Splicing / Q000502:physiology*; D000818:Animals; D015703:Antigens, CD; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism; D002923:Cilia / Q000502:physiology / Q000648:ultrastructure; D006224:Cricetinae; D004822:Epididymis / Q000502:physiology* / Q000648:ultrastructure; D004847:Epithelial Cells / Q000378:metabolism / Q000648:ultrastructure; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012671:Seminiferous Tubules / Q000378:metabolism / Q000648:ultrastructure; D013094:Spermatozoa / Q000378:metabolism / Q000648:ultrastructure; D013737:Testis / Q000502:physiology* / Q000648:ultrastructure
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; D010455:Peptides; C000606024:Prom1 protein, mouse; D020033:Protein Isoforms