1. Putative Mammalian Taste Receptors
2. A Novel Family of Divergent Seven-Transmembrane Proteins
3. . The algorithm examines the physicochemical properties of the amino acids in an open reading frame (ORF) and then uses a nonparametric discriminant function to identify ORFs likely to encode multitransmembrane domain proteins.
4. The first exon of 23A.1b (Fig. 1) was identified by the computer algorithm described in (2). Examination of the genomic DNA surrounding the first exon of 23A.1b identified other exons and the genomic structure of this gene was determined with RT-PCR. Using the sequence of this gene we performed an extensive series of tBLASTn searches of the Berkeley Drosophila Genome Project (BDGP) sequence database (available at ) which identified ORFs of 38 other genes of the GR family. The full sequences of these genes were identified by an analysis of the genomic DNA flanking these ORFs as described in (2) using the Drosophila intron-exon consensus splice sequences and RT-PCR analysis. The 39 genes encode a total of 43 proteins. The National Center for Biotechnology Information (NCBI) accession number of the BDGP genomic clone on which each transcript is found and the sequence range in the genomic clone for the predicted coding region are given as follows for each GR transcript shown in Fig. 1 (NCBI and BDGP data are as of 16 October 1999): transcript GR21D.1 accession number range 34784–33509; GR22B.1 31740–30551; GR23A.1a 108490–106118; GR23A.1b 107351–106118; GR32D.1 19779–21141; GR39D.1 62553–64348; GR39D.2a 9170–16119; GR39D.2b 10410–16119; GR39D.2c 12989–16119; GR39D.2d 14750–16119; GR43C.1 50105–51583; GR47A.1 114644–115920; GR58A.1 62323–61087; GR58A.2 62511–63791; GR58A.3 65521–64229; GR59D.1 68825–70050; GR59D.2 70261–71505; GR59E.1 30167–31539; and GR59E.2 30036–28714. Accession numbers for the other genes are as follows (data are as of 5 January 2000) (complete sequences are available for the first four and only partial sequences are available for the remaining genes; LU location unknown): transcript GR1F.1 accession number range 7301–8711; GR47F.1 42838–44204; GR68D.1 46040–44916; GR77E.1 104929–103117; GR28A.1 66711–66973; GR57B.1 102661–103185; GR65C.1 23136–24215; GR93F.1 35043–35228; GR93F.2 2781–2650; GR93F.3 4271–4143; GR93F.4 6482–5559; GR94E.1 72472–72308; GR97D.1 121300–121977; GR98B.1 45506–46916; GR98B.2 10695–10784; GR98B.3 45189–45284; GR98B.4 39658–39765; GRLU.1 22141–21398; GRLU.2 10997–11122; GRLU.3 43210–43612; GRLU.4 BACR28P1-T7 28–129; GRLU.5 BACR28P1-T7 388–734; GRLU.6 BACR06I03-T7 1028–48; and GRLU.7 AC012799 8212–8123.
5. All of the GR proteins were identified as GPCRs when the algorithm was modified to distinguish previously described GPCRs from ion channels. The algorithm was set to positively identify 95% of previously described GPCRs with 4.3% false positives. Most ion channels have six transmembrane domains.