Isolation and characterization of the rat glutamine synthetase-encoding gene

From a rat genomic library in phage λCharon4A, a complete glutamine synthetase-encoding gene was isolated. The gene is 9.5–10 kb long, consists of seven exons, and codes for two mRNA species of 1375 nucleotides (nt) and 2787 nt, respectively. For both mRNAs, full-lenght cDNAs containing a short poly(A) tract were identified. The sequences of the entire mRNA and of the exon-intron transitions were determined. The smaller mRNA is identical to the 5′ 1375 nt of the long mRNA and contains the entire protein-coding region. The position of the transcription start point was mapped. Within the first 118 bp of promoter sequence, a (T)ATAA-box, a CCAAT-box and an SP1-binding site were identified.