PKCtheta II, a new isoform of protein kinase C specifically expressed in the seminiferous tubules of mouse testis.
Protein kinase C (PKC) theta, a Ca(2+)-independent isoform of PKC, has been known to be expressed in skeletal muscle and T cells. In the present study, we isolated and characterized a smaller transcript expressed in the mouse testis, the cDNA of which is referred hereafter as PKCthetaII and the original PKCtheta as PKCthetaI. The cDNA clone of PKCthetaII has 2184 base pairs and 464 amino acids in the possible open reading frame, consisting of the 5' unique sequence of 20 amino acids and the PKCthetaI sequence of 444 amino acids. Genomic DNA analysis revealed that transcription of PKCthetaII is initiated from the PKCthetaII-specific exon, which is located between exons 7 and 8 of the PKCtheta gene, indicating that alternative splicing is the mechanism by which PKCthetaII is generated. PKCthetaII is expressed exclusively in the testis in an age-dependent manner with sexual maturation. In situ hybridization and reverse transcription-polymerase chain reaction of microdissected tissues clearly demonstrated that PKCthetaII is expressed in the seminiferous tubules of the mouse testis. Consistent with its molecular structure lacking the C1 regulatory domain, PKCthetaII is constitutively active as determined by an in vitro kinase assay, being independent of PKC activators, e.g. phosphatidylserine and phorbol ester. PKCthetaII may play a crucial role in spermatogenesis or some related function of the testis.
Niino
Y S
YS
Institute of Molecular Oncology, Department of Pathology, Faculty of Dentistry and Center for Biotechnology, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. niino@med.showa-u.ac.jp
Irie
T
T
Takaishi
M
M
Hosono
T
T
Huh
N
N
Tachikawa
T
T
Kuroki
T
T
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D019556:COS Cells; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D005091:Exons; D015723:Gene Library; D015151:Immunoblotting; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000737:chemistry*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D011493:Protein Kinase C / Q000737:chemistry*; D000074121:Protein Kinase C-theta; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012671:Seminiferous Tubules / Q000201:enzymology* / Q000473:pathology; D013997:Time Factors; D014158:Transcription, Genetic
D018076:DNA, Complementary; D007527:Isoenzymes; D020033:Protein Isoforms; D012333:RNA, Messenger; C489593:Prkcq protein, mouse; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta