Cloning and expression study of the mouse tetrodotoxin-resistant voltage-gated sodium channel alpha subunit NaT/Scn11a

We have cloned a tetrodotoxin-resistant (TTX-R) voltage-gated sodium channe l ex subunit from a mouse cDNA library and designated it as NaT, It encodes 1765 amino acid residues and is virtually identical to that of Scn11a, whi ch has been reported recently, except for 40 nt and 14 aa substitutions. Th e amino acid identity of NaT/Scn11a with rat NaN/SNS2 is 88%, NaT/Scn11a wa s mapped to mouse chromosome 9F3-F4 by fluorescence in situ hybridization ( FISH), While rat NaN/ SNS2 has been reported to be expressed specifically i n the peripheral sensory neurons, NaT/Scn11a is expressed not only in the p eripheral sensory neurons but also in the spinal cord, uterus, testis, ovar y, placenta, and small intestine. NaT is detectable in mouse embryos 15 day s postcoitus (p.c.), around the phase of organogenesis and gonadal differen tiation. These findings demonstrate a unique distribution of NaT/ Scn11a an d suggest some of its roles in the above-mentioned processes. (C) 2000 acad emic Press.