TISSUE-SPECIFIC VARIANTS OF GLUTAMATE TRANSPORTER GLT-1

cDNA cloning of glutamate transporter GLT-1 from mouse brain and liver has revealed that 5'-ends of the messages are different between brain and liver, In addition, one of the GLT-1 cDNAs isolated from liver ha s been found to possess a 3'-end different from those of the others, R everse transcription polymerase chain reaction (RT-PCR) amplification using primers specific for altered 5'-ends has confirmed that brain an d liver messages possess their own. specific 5'-ends, Both of the two 3'-ends have been demonstrated by RT-PCR to be present not only in liv er but also in brain, indicating both brain and Liver GLT-1 possess tw o types of 3'-ends, Although functional properties are not changed by the alteration of N-termini and C-termini when expressed in Xenopus la evis oocytes, co-expression of two liver type GLT-1 with different C-t ermini (mGLT-1A and mGLT-1B) has been found to result in the increase in V-max of transport without changing K-m, These results suggest the tissue specific alternative splicing at 5'-ends of GLT-1 messages and the interesting association of spliced variants with different C-termi ni. (C) 1997 Federation of European Biochemical Societies.