Gene, 129 (1993) 275-278 0 1993 Elsevier Science Publishers B.V. All rights reserved. 0378-l 119/93/$06.00 GENE 07119 cDNA clones from the olfactory organ of the spiny lobster encode a protein related to eukaryotic glutamine synthetase* (Recombinant DNA; cDNA clones; zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Pant&us argus) Henry G. Trapido-Rosenthala,b, Paul J. Linsera, Robert M. Greenberg”, Richard A. Gleesona and William E.S. Carra zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA “The W hitney Laboratory, Vnioersity of Florida, St. Augustine, FL 32086-8623, USA. Tel. (904) 461-4000; and ‘Bermuda Biological Station for Research, St. GeorgeS GE 01, Bermuda Received by D.M. Skinner: 4 August 1992; Revised/Accepted: 30 November/23 February 1993; Received at publishers: 25 February 1993 275 SUMMARY We report here the nucleotide (nt) sequence of clones from a lobster olfactory organ cDNA library encoding a protein homologous to glutamine synthetase (GS) from eukaryotes. The cDNA for the lobster putative GS is 2045 bp in length, and includes a S-untranslated region 55 nt in length, a 1083-nt open reading frame, and a 907-nt 3’-untranslated region. The encoded protein shows 65, 64, and 63% identity with the reported GS sequences of chicken, human and fruit fly, respectively. INTRODUCTION The enzyme glutamine synthetase (GS) (L-gluta- mate:ammonia ligase; EC 6.3.1.2) catalyzes the formation of glutamine by means of the ATP-dependent condensa- tion of glutamic acid and ammonia. In the central ner- vous system, GS is localized to glial cells and plays important roles in the metabolism of nitrogen and of aa neurotransmitters (Norenberg, 1979; Linser, 1985). In particular, it works in conjunction with sodium- dependent aa transporters to clear the excitatory neuro- transmitter glutamic acid from glutamatergic synapses (Derouiche and Frotscher, 1991). Correspondence to: Dr. H.G. Trapido-Rosenthal, Bermuda Biological Station for Research, Ferry Reach, St. George’s GE 01, Bermuda. Tel. (809) 297-1880; Fax (809) 2978143. * On request, the authors will supply detailed experimental evidence for the conclusions reached in this Short Communication. Abbreviations: aa, amino acid(s); bp, base pair(s); cDNA, DNA comple- mentary to mRNA; GS, glutamine synthetase; GS, gene (DNA) encod- ing GS; kb, kilobase( nt, nucleotide(s); oligo, oligodeoxyribo- nucleotide; ORF, open reading frame; Pa, Pam&us argus; PCR, poly- merase chain reaction. The olfactory system of the spiny lobster consists of arrays of between 1000 and 2000 chemosensory sensilla on each lateral filament of the antennules. The approxi- mately 250 picoliter volume of each sensillum is filled with the highly-branched dendrites of over 300 chemosen- sory neurons, the distal processes of a population of glia- like auxiliary cells, and a viscous, proteinaceous, receptor lymph (Griinert and Ache, 1988; Gleeson et al., 1993). Among these chemoreceptor cells are those that selec- tively respond to different aa, including glutamate, that the animal encounters in its marine environment (Carr et al., 1987). Cells within the sensilla also possess enzymes and uptake systems that can remove odorants from the vicinity of the chemosensory receptors (Trapido- Rosenthal et al., 1988, 1990). We report here that a cDNA library made from mRNA extracted from the olfactory tissue contains a nt sequence that may encode the glutamate-metabolizing enzyme GS. EXPERIMENTAL AND DISCUSSION (a) Cloning and characterization of olfactory cDNAs A lobster olfactory organ cDNA library in h-ZAP11 (Stratagene, La Jolla, CA, USA) was screened for inserts