Molecular cloning of haploid germ cell-specific tektin cDNA and analysis of the protein in mouse testis

AbstractTektins are a class of proteins that form filamentous polymers in the walls of ciliary and flagellar microtubules. We report here the molecular cloning of a new member of the tektin family, tektin-t, identified from a mouse haploid germ cell-specific cDNA library. Tektin-t mRNA encodes a protein of 430 deduced amino acids possessing RSNVELCRD, the conserved sequence of tektin family proteins. Western blotting showed a single band having a molecular weight of 86 kDa in the mouse testis. Immunohistochemistry of the testis showed that tektin-t is localized in the flagella of elongating spermatids from developmental step 15 to maturity

Electron Microscope Studies on the Structural Complex of Transverse Tubules and Sarcoplasmic Reticulum in Scorpionfish Swimbladder Muscles

To clarify the distribution of transverse tubule-sarcoplasmic reticulum (T-SR) com-plexes in the swimbladder muscle (SBM) of the scorpionfish (Sebastiscus marmoratus ), elec-tron microscope observations were performed. In the anterior part of the SBM, Z-type triads were exclusively observed, in contrast to the regular distribution of AI- and Z-type triads with pentads and heptads in the posterior part of the SBM reported in our previous paper. Various body muscles of scorpionfish contained only Z-type triads. Furthermore, SBM and body wall muscles (BWM) in other sound-producing fishes each contained only one type of triadic con-tacts. In the posterior fibers of scorpionfish SBM, feet on the junctional SR membrane formed a square lattice with three or more vertical lines and numerous horizontal rows. Isolation and identification of ryanodine receptor (RyR) revealed that αRyR and βRyR coexist in the SBM and BWM of scorpionfish. Anti-αRyR and βRyR antibodies were produced in rabbits, and im-munoelectron microscopy with these antibodies demonstrated that both αRyR and βRyR form parallel lines respectively on the same junctional membrane as AI- and Z-type triads. The re-sults are discussed in connection with the anatomical features and function of the swimbladder.Full-Length Pape