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GPR99, a new G protein-coupled receptor with homology to a new subgroup of nucleotide receptors.

Wittenberger T, Hellebrand S, Munck A, Kreienkamp HJ, Schaller HC, Hampe W - BMC Genomics (2002)

Bottom Line: The mRNA of GPR99 was found in kidney and placenta.We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors.Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

View Article: PubMed Central - HTML - PubMed

Affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Martinistr, 52, D-20246 Hamburg, Germany. timo.wittenberger@altanapharma.com

ABSTRACT

Background: Based on sequence similarity, the superfamily of G protein-coupled receptors (GPRs) can be subdivided into several subfamilies, the members of which often share similar ligands. The sequence data provided by the human genome project allows us to identify new GPRs by in silico homology screening, and to predict their ligands.

Results: By searching the human genomic database with known nucleotide receptors we discovered the gene for GPR99, a new orphan GPR. The mRNA of GPR99 was found in kidney and placenta. Phylogenetic analysis groups GPR99 into the P2Y subfamily of GPRs. Based on the phylogenetic tree we propose a new classification of P2Y nucleotide receptors into two subgroups predicting a nucleotide ligand for GPR99. By assaying known nucleotide ligands on heterologously expressed GPR99, we could not identify specifically activating substances, indicating that either they are not agonists of GPR99 or that GPR99 was not expressed at the cell surface. Analysis of the chromosomal localization of all genes of the P2Y subfamily revealed that all members of subgroup "a" are encoded by less than 370 kb on chromosome 3q24, and that the genes of subgroup "b" are clustered on one hand to chromosome 11q13.5 and on the other on chromosome 3q24-25.1 close to the subgroup "a" position. Therefore, the P2Y subfamily is a striking example for local gene amplification.

Conclusions: We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors. Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

No MeSH data available.


Northern blot analysis of human GPR99.
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Figure 1: Northern blot analysis of human GPR99.

Mentions: Performing TBLASTN searches of the human genomic database with the known nucleotide GPRs we identified an additional ORF, which we named GPR99. The ORF reaches from bp 140188 to 141201 of the BAC clone with the accession number AC026756.15. The putative start codon in a Kozak context is located 15 bp behind an in-frame stop codon. The last 20 bp of the ORF and the 3' UTR are found on an EST clone derived from thyroid epithelium (AW827323). Sequencing the entire EST clone from the I.M.A.G.E consortium [3], which was supplied by the Resource Center of the German Human Genome Project at the Max-Planck-Institute for Molecular Genetics, confirmed the genomic sequence behind the coding region for transmembrane domain six. To show mRNA expression of full-length GPR99, we amplified the entire coding region together with the upstream stop codon from a human placenta cDNA library by PCR. Direct sequencing of the PCR product was in perfect accordance with the genomic data. The sequence was submitted to GenBank under accession number AF370886. mRNA expression of GPR99 was proven by northern blot analysis. A 3.0 kb mRNA was detected in kidney and, to a lower extend, in placenta (Fig. 1).


GPR99, a new G protein-coupled receptor with homology to a new subgroup of nucleotide receptors.

Wittenberger T, Hellebrand S, Munck A, Kreienkamp HJ, Schaller HC, Hampe W - BMC Genomics (2002)

Northern blot analysis of human GPR99.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC117779&req=5

Figure 1: Northern blot analysis of human GPR99.
Mentions: Performing TBLASTN searches of the human genomic database with the known nucleotide GPRs we identified an additional ORF, which we named GPR99. The ORF reaches from bp 140188 to 141201 of the BAC clone with the accession number AC026756.15. The putative start codon in a Kozak context is located 15 bp behind an in-frame stop codon. The last 20 bp of the ORF and the 3' UTR are found on an EST clone derived from thyroid epithelium (AW827323). Sequencing the entire EST clone from the I.M.A.G.E consortium [3], which was supplied by the Resource Center of the German Human Genome Project at the Max-Planck-Institute for Molecular Genetics, confirmed the genomic sequence behind the coding region for transmembrane domain six. To show mRNA expression of full-length GPR99, we amplified the entire coding region together with the upstream stop codon from a human placenta cDNA library by PCR. Direct sequencing of the PCR product was in perfect accordance with the genomic data. The sequence was submitted to GenBank under accession number AF370886. mRNA expression of GPR99 was proven by northern blot analysis. A 3.0 kb mRNA was detected in kidney and, to a lower extend, in placenta (Fig. 1).

Bottom Line: The mRNA of GPR99 was found in kidney and placenta.We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors.Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

View Article: PubMed Central - HTML - PubMed

Affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Martinistr, 52, D-20246 Hamburg, Germany. timo.wittenberger@altanapharma.com

ABSTRACT

Background: Based on sequence similarity, the superfamily of G protein-coupled receptors (GPRs) can be subdivided into several subfamilies, the members of which often share similar ligands. The sequence data provided by the human genome project allows us to identify new GPRs by in silico homology screening, and to predict their ligands.

Results: By searching the human genomic database with known nucleotide receptors we discovered the gene for GPR99, a new orphan GPR. The mRNA of GPR99 was found in kidney and placenta. Phylogenetic analysis groups GPR99 into the P2Y subfamily of GPRs. Based on the phylogenetic tree we propose a new classification of P2Y nucleotide receptors into two subgroups predicting a nucleotide ligand for GPR99. By assaying known nucleotide ligands on heterologously expressed GPR99, we could not identify specifically activating substances, indicating that either they are not agonists of GPR99 or that GPR99 was not expressed at the cell surface. Analysis of the chromosomal localization of all genes of the P2Y subfamily revealed that all members of subgroup "a" are encoded by less than 370 kb on chromosome 3q24, and that the genes of subgroup "b" are clustered on one hand to chromosome 11q13.5 and on the other on chromosome 3q24-25.1 close to the subgroup "a" position. Therefore, the P2Y subfamily is a striking example for local gene amplification.

Conclusions: We identified a new orphan receptor, GPR99, with homology to the family of G protein-coupled nucleotide receptors. Phylogenetic analysis separates this family into different subgroups predicting a nucleotide ligand for GPR99.

No MeSH data available.