CHARACTERIZATION OF THE 5'-REGION OF THE RAT-BRAIN GLYCINE TRANSPORTER GLYT2 GENE - IDENTIFICATION OF A NOVEL ISOFORM

We have identified two alternative 5' ends for the GLYT2 glycine trans porter in rat brain DNA by using rapid amplification of cDNA ends (RAC E) analysis. Study of the genomic DNA revealed that the isoform divers ity is generated by alternative use of exons Ia or Ib, respectively. U pon translation, the mRNA corresponding to the novel isoform GLYT2b wo uld yield a protein five amino acids longer than the previously charac terized isoform GLYT2a. Both forms display similar regional distributi on and kinetics characteristics. However, whereas GLYT2a is able to ac tively accumulate glycine into transfected COS cells, GLYT2b seems onl y to exchange (or release) glycine. (C) 1998 Elsevier Science Ireland Ltd.