Fig. 2. Alignment of vertebrate glutamine synthetase genes. Identity to the consensus sequence is shown with a dash, while an insertion/deletion is shown with an asterisk and a stop codon with an exclamation mark. Tentative active site residues of the glutamate binding site based on the residues identified in Salmonella typhimurium (Gill and Eisenberg 2001) are shown in bold, underlined and indicated with a check mark '. The location of intron 4 is indicated by a downward arrow (). Three periods (...) indicate incomplete or missing sequence information. The sequences are identified with a four-letter code based on their species name and followed by either their unique GenBank accession number, Joint Genome Institute genescan model number or, for sequences reported here, a unique gene indicator, i.e. GS01. Species included are Oncorhynchus mykiss, Onmy; Danio rerio, Dare; Opsanus beta, Opbe; Bostrichthys sinensis, Bosi; Takifugu rubripes, Fugu; Xenopus laevis, Xela; Cricetulus griseus, Crgr; Acomys cahirinus, Acca; Rattus norvegicus, Rano; Mus musculus, Mumu; Sus scrofa, Susc; Homo sapiens, Hosa; Gallus gallus, Gaga; Heterodontus francisci, Hefr and Squalus acanthias, Sqac.