Tektin5, a new Tektin family member, is a component of the middle piece of flagella in rat spermatozoa

• Published in: Molecular reproduction and development Vol. 75; no. 4; pp. 650 - 658
• Main Authors: Murayama, Emi, Yamamoto, Etsuko, Kaneko, Takane, Shibata, Yosaburo, Inai, Tetsuichiro, Iida, Hiroshi
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-04-2008; Wiley-Liss
• Subjects: Amino Acid Sequence; Animals; Antibodies - chemistry; Antibody Specificity; Antigen-Antibody Reactions; axoneme; Biological and medical sciences; Cloning, Molecular; Flagella - chemistry; flagellum; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Humans; Immunohistochemistry; Male; Mammalian male genital system; Mice; Microscopy, Confocal; Microscopy, Immunoelectron; Microtubule Proteins - genetics; Microtubule Proteins - immunology; Microtubule Proteins - isolation & purification; Molecular Sequence Data; Morphology. Physiology; Phylogeny; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; sperm; Spermatozoa - chemistry; Spermatozoa - ultrastructure; tektin; testis; Tissue Embedding; Urea - chemistry; Vertebrates: reproduction; Rat; Semen; Rodentia; Flagellum; sperm; testis; Gene expression; Testicle; tektin; Male genital system; Vertebrata; Mammalia; Animal; axoneme; Localization
• ISSN: 1040-452X; 1098-2795
• DOI: 10.1002/mrd.20804

Tektins are composed of a family of filament‐forming proteins localized in cilia and flagella. Four types of mammalian Tektins have been reported, and at least two types of Tektins, Tektin2 and Tektin4, have been verified to be present in sperm flagella. A new member of the TEKTIN gene family, which was designated as rat Tektin5, was obtained by PCR technique. Rat Tektin5 cDNA consists of 1,674 bp encoding a 62.8 kDa protein of 558 amino acids. Tektin5 protein contains a Tektin domain as well as a nonapeptide signature sequence that is a prominent feature of Tektin proteins. RT‐PCR analysis indicated that Tektin5 was predominantly expressed in testis and that its expression was up‐regulated during testis development. Immunoblot analyses revealed that Tektin5 is present in sperm flagella but not in heads and that it is completely released from rat spermatozoa by 6 M urea treatment, but not extracted by 1% Triton X‐100 and 0.6 M potassium thiocyanate. Confocal laser scanning microscopy revealed that Tektin5 was located in the middle piece of flagella in rat spermatozoa with no immunolabeling in the heads and the principal piece. Immunogold electron microscopy adopting pre‐embedding method discovered that Tektin5 is predominantly associated with the inner side of the mitochondrial sheath. Tektin5 might work as a middle piece component requisite for flagellar stability and sperm motility. Mol. Reprod. Dev. 75: 650–658, 2008. © 2007 Wiley‐Liss, Inc.