ANOTHER MEMBER OF THE CYCLIC NUCLEOTIDE-GATED CHANNEL FAMILY, EXPRESSED IN TESTIS, KIDNEY, AND HEART

Cyclic nucleotide-gated cation channels are essential in visual and ol factory signal transduction. An additional member of the cGMP-gated ch annel family, termed CNG-3, has been cloned from bovine kidney. Its de duced amino acid sequence is 60% and 62% identical with the CNG-channe l proteins from bovine rod outer segment and bovine olfactory epitheli um, respectively. Northern analysis and sequences amplified by the PCR showed that the CNG-3 mRNA is present in testis, kidney, and heart. C alcium permeated the expressed channel in the presence of extracellula r Mg2+ and Na+ at membrane potentials from -100 to +45 mV. It is likel y that CNG-3 protein is responsible for cGMP-induced Ca2+ entry in cel ls other than sensory cells.