Jr. Yi et al., EXPRESSION CLONING OF A RAT HEPATIC REDUCED GLUTATHIONE TRANSPORTER WITH CANALICULAR CHARACTERISTICS, The Journal of clinical investigation, 93(4), 1994, pp. 1841-1845
Using the Xenopus oocyte expression system, we have previously identif
ied an similar to 4-kb fraction of mRNA from rat liver that expresses
sulfobromophthalein-glutathione (BSP-GSH)-insensitive reduced glutathi
one (GSH) transport (Fernandez-Checa, J., J. R. Yi, C. Garcia-Ruiz, Z.
Knezic, S. Tahara, and N. Kaplowitz. 1993. J. Biol. Chem. 268:2324-23
28). Starting with a cDNA library constructed from this fraction, we h
ave now isolated a single clone that expresses GSH transporter activit
y. The cDNA for the rat canalicular GSH transporter (RcGshT) is 4.05 k
b with an open reading frame of 2,505 nucleotides encoding for a polyp
eptide of 835 amino acids (95,785 daltons). No identifiable homologies
were found in searching various databases. An similar to 96-kD protei
n is generated in in vitro translation of cRNA for RcGshT. Northern bl
ot analysis reveals a single 4-kb transcript in liver, kidney, intesti
ne, lung, and brain. The abundance of mRNA for RcGshT in rat liver inc
reased 3, 6, and 12 h after a single dose of phenobarbital. Insensitiv
ity to BSP-GSH and induction by phenobarbital, unique characteristics
of canalicular GSH secretion, suggest that RcGshT encodes for the cana
licular GSH transporter.