A mRNA molecule encoding truncated excitatory amino acid carrier 1 (EAAC1) protein (EAAC2) is transcribed from an independent promoter but not an alternative splicing event.
Glutamate transporter EAAC1 removes excitatory neurotransmitter in central nervous system, and also absorbs glutamate in epithelia of intestine, kidney, liver and heart for normal cell growth. When a mouse cDNA was screened using EAAC1 cDNA fragment as probe in our lab, a transcript (GenBank U75214) encoding an EAAC1 protein with 148 residues truncated at N-terminal was cloned and named as EAAC2. Sequence analysis shows that EAAC2 has it's own start code and unique 5'UTR that is different from that of EAAC1. A mouse genomic library was screened and a positive clone including EAAC1 CDS was sequenced (GenBank AF 322393) and indicates that normal EAAC1 transcript (GenBank U73521) is transcribed from 10 exons in terms of exon I, II, III, IV, V, VI, VII, VIII, IX, X, and EAAC2 transcript is consisted by exons from IV to IX as same as that of EAAC1 and with its unique exon beta upstream to exon IV and exon delta downstream to IX. EAAC2 transcript has a cluster of transcriptional start sites not overlapping with the transcriptional start sites of EAAC1. These results indicate that EAAC2 is transcribed from an independent promoter but not an alternative splicing event.
Jin
Xiao Ping
XP
Laboratory of Molecular Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.
Peng
Ji Bin
JB
Huang
Fang
F
Zhu
Ya Ni
YN
Fei
Jian
J
Guo
Li He
LH
D020121:5' Untranslated Regions; D017398:Alternative Splicing; D027322:Amino Acid Transport System X-AG / Q000235:genetics*; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D050580:Excitatory Amino Acid Transporter 3; D005091:Exons; D015870:Gene Expression; D050491:Glutamate Plasma Membrane Transport Proteins; D007438:Introns; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics*; D027981:Symporters / Q000235:genetics*; D014018:Tissue Distribution; D014158:Transcription, Genetic
D020121:5' Untranslated Regions; D027322:Amino Acid Transport System X-AG; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D012333:RNA, Messenger; C493399:Slc1a1 protein, mouse; D027981:Symporters