title: Molecular dissection of ODF2/Cenexin revealed a short stretch of amino acids necessary for targeting to the centrosome and the primary cilium.
abstract: The outer dense fiber protein ODF2 is the major component of the sperm tail cytoskeleton and a critical component of the mature centriole of the centrosome. Centriole maturation involves the formation of appendages and the recruitment of ODF2/Cenexin. ODF2 and Cenexin are alternative splice variants that differ in a short stretch of amino acids at their N-terminal regions encoded by exon 3b. Whereas Cenexin is ubiquitously expressed, Odf2 is the predominant transcript of testes [Hüber, D., Hoyer-Fender, S., 2007. Alternative splicing of exon 3b gives rise to ODF2 and Cenexin. Cytogenet. Genome Res. 119, doi:10.1159/000109621]. Here, we show that testicular expression of Odf2 correlates with spermiogenesis and ongoing sperm tail formation thus implicating functional differences between ODF2 and Cenexin. By generation of a series of ODF2/Cenexin deletion constructs fused to GFP and inspection of their subcellular localization in transfected NIH3T3 cells we found that a peptide of 42 amino acids specific for Cenexin is necessary for targeting ODF2/Cenexin to the centrosome and the primary cilium. Additionally, this region is also necessary for the formation of ODF2/Cenexin fibers that are associated with acetylated microtubules. Centrosomal targeting of ODF2/Cenexin does not depend on dynein-mediated transport further supporting an alternative targeting mechanism. However, part of the C-terminal coiled-coil region of ODF2 is also important in centrosomal/ciliary targeting and fiber formation presumably by supporting self-association and the formation of higher-order structures.
authors.affiliation: Johann-Friedrich-Blumenbach-Institut für Zoologie, Anthropologie und Entwicklungsbiologie, Universität Göttingen, GZMB, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Hüber
authors.forename: Stephanie
authors.initials: S
authors.lastname: Geisler
authors.forename: Sebastian
authors.initials: S
authors.lastname: Monecke
authors.forename: Sigrid
authors.initials: S
authors.lastname: Hoyer-Fender
mesh_terms: D000107:Acetylation; D000818:Animals; D002460:Cell Line; D002502:Centrioles / Q000378:metabolism; D018385:Centrosome / Q000378:metabolism*; D002923:Cilia / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D000072159:Dynactin Complex; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013082:Sperm Tail / Q000378:metabolism; D013091:Spermatogenesis / Q000502:physiology*; D013737:Testis / Q000378:metabolism*
chemical_list: D000072159:Dynactin Complex; D006360:Heat-Shock Proteins; D008869:Microtubule-Associated Proteins; C490106:Odf2 protein, mouse; D011993:Recombinant Fusion Proteins