title: 'Choline/orphan V8-2-1/creatine transporter' mRNA is expressed in nervous, renal and gastrointestinal systems.
abstract: Several cDNAs with substantial sequence homologies to members of the neurotransmitter transporter gene family currently remain 'orphan' transporters, without clearly-identified substrates. We were concerned that a cDNA 'V8-2-1' isolated from a ventral midbrain cDNA library in this laboratory and a virtually-identical cDNA 'CHOT1' reported by Mayser et al. [J. Neurochem., 20 (1973) 581-593] might represent such an orphan. Despite initial reports that it could mediate some choline uptake; neither CHOT1 nor V8-2-1 was demonstrated to confer pharmacologically appropriate choline uptake not already present in either Xenopus oocytes or COS cells. Determination of the regional and tissue-specific distribution of mRNA hybridizing with V8-2-1 cDNA was undertaken to aid in identifying its function. Examination of the distribution of V8-2-1 expression reveals several novel features of this transporter gene family member's distribution, including several features that add to current evidence suggesting that the clone may not encode the classical pharmacologically-defined, hemicholinium-3 sensitive high affinity transporter of cholinergic neurons. These data fit with and extend recent data that suggest that this cDNA represents creatine transporter, and provide initial documentation of its regional distribution in brain.
authors.affiliation: Molecular Neurobiology Branch, National Institute on Drug Abuse, Johns Hopkins University School of Medicine, Baltimore, MD 21224.
authors.forename: A M
authors.initials: AM
authors.lastname: Gonzalez
authors.forename: G R
authors.initials: GR
authors.lastname: Uhl
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D002522:Chlorocebus aethiops; D002794:Choline / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004064:Digestive System / Q000378:metabolism*; D006426:Hemicholinium 3 / Q000494:pharmacology; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D009865:Oocytes; D009928:Organ Specificity; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D027981:Symporters; D014981:Xenopus
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D012333:RNA, Messenger; D027981:Symporters; C080679:creatine transporter; C075746:Slc6a8 protein, rat; D006426:Hemicholinium 3; D003401:Creatine; D002794:Choline