Molecular characterization of a voltage-gated potassium channel expressed in rat testis.
Jacob-A; Hurley-IR; Goodwin-LO; Cooper-GW; Benoff-S
Mol Hum Reprod 2000 Apr; 6(4):303-313
Potassium (K(+)) channels are present in both mammalian testis and spermatozoa. Immunofluorescent detection of sperm-bound biotinylated charybdotoxin, an inhibitor of Ca(2+)-activated and of delayed rectifier K(+) channels, indicated that these ion channels are uniformly distributed over the surface of both heads and tails of unfixed rat epididymal spermatozoa. Reverse transcription-polymerase chain reaction (RT-PCR) analysis on rat testis RNA with PCR primers, based on known nucleotide sequences of different classes of K(+) channels, amplified sequences homologous to delayed rectifier K(+) channels. In-situ RT-PCR on rat testis sections showed that these K(+) channel transcripts are present in the cytoplasm of primary spermatocytes and post-meiotic elongating spermatids. Northern blot analysis of various rat tissues identified multiple K(+) channel transcripts, some of which were observed only in testis. An attempt to obtain a full length rat testis K(+) channel cDNA sequence gave an assembled sequence of 2693 base pairs with >90% homology to a delayed rectifier K(+) channel, Kv1.3. A method for rapid amplification of cDNA ends was employed to amplify the 5' sequences of the rat testis cDNA but a unique sequence could not be obtained. DNA sequencer traces suggest that multiple related K(+) channels which differed at their 5' ends were amplified in rat testis.
Fertility; Morphology; Biomarkers; Reproductive-hazards; Reproductive-system; Potassium-compounds; Laboratory-animals; Animal-studies; Animals; Spermatozoa; Spermatogenesis;
Author Keywords: charybdotoxin labelling; potassium channel; sperm membrane; spermatozoa; testis
North Shore University Hospital, 300 Community Drive, Boas-Marks Biomedical Science Research Center - Room 119, Manhasset, New York 11030, USA
Research Tools and Approaches: Exposure Assessment Methods
Molecular Human Reproduction
North Shore University Hospital, Manhasset, New York