Molecular cloning and characterization of fox testis kinectin

Kinectin was isolated and characterized from a fox testis cDNA library using a monoclonal antibody (FTA-1) raised against testis surface proteins. The cDNA sequence of 4,479 nucleotides encodes an ORF of 1,330 amino acids (aa) with high homology to mouse, human, and chicken kinectins (GenBank Accession Number AF095786). Southern analysis was used to show that genes homologous to kinectin are present in several mammal species and in at least one marsupial, but not in bacteria. Alternatively spliced forms of fox kinectin were identified, and one of these is uniquely expressed in brain and spleen tissues. Kinectin expression was highest in testis relative to other tissues examined. Sequence analysis and comparisons between species revealed that kinectin encodes multiple α-helical coiled coils predicted to form dimers, and is, therefore, likely to exist as a dimer. The results presented in this article suggest that kinectin is required for spermatogenesis, but is not a likely candidate for use in immunocontraceptive vaccines.