A glutamate dehydrogenase gene sequence
Résumé
A Chlorella sorokiniana genomic DNA library was screened with a NADP-specific glutamate dehydrogenase (GDH) cDNA. Two putative GDH sequences were isolated. One sequence is typically eukaryotic in that its coding region is interrupted by many introns (1). Southern blots showed that C. sorokiniana DNA contains the eukaryotic GDH gene but the second sequence could not be detected. The second sequence has characteristics of a prokaryotic GDH gene. The gene was expressed in E. coli CLR207recA (qdhA; 2) from a multicopy plasmid, giving GDH activity 54-fold higher than basal level in untransformed cells. The cloned gene is not positioned near a plasmid promoter, suggesting expression occurred from its own promoter. The proposed coding region is highly homologous to other cloned bac