Elsevier

Genomics

Volume 87, Issue 2, February 2006, Pages 254-264
Genomics

Genomic and supragenomic structure of the nucleotide-like G-protein-coupled receptor GPR34

https://doi.org/10.1016/j.ygeno.2005.10.001Get rights and content
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Abstract

Directed cloning approaches and large-scale sequencing of several vertebrate genomes unveiled many new members of the G-protein-coupled receptor (GPCR) superfamily, among them GPR34. Initial studies showed that GPR34 is an evolutionarily old GPCR structurally related to a group of ADP-like receptors. To gain insight into the genomic organization, regulation of expression, and supragenomic diversification of GPR34 several vertebrate species were analyzed. In contrast to the obviously intronless coding region GPR34 displays an evolutionary preserved 5′ noncoding intron–exon structure. Further, an alternatively used cryptic intron was identified within the coding region, which shortens the N terminus by 47 amino acids. Ubiquitous expression of GPR34 is driven by genomic sequences upstream of at least two transcriptional start regions in mouse and rat but only one region in human. In rodents, both promoters are active in all tissues investigated, but the level of activity is tissue-specific. At the translational level, several conserved in-frame AUGs within the first 150 bp of the coding region may serve as start points for translation in human and other mammals. Combinatory mutagenesis and expression of reporter constructs confirmed these multiple translational start points and revealed a preference for the second in-frame AUG in human GPR34. Our data show that multiple translation initiation starts and alternative splicing contribute to the supragenomic diversification of GPR34.

Abbreviations

GPCR
G-protein-coupled receptor
hGPR34
human GPR34
mGPR34
mouse GPR34
ORF
open reading frame
ROX
carboxy-X-rhodamine
UTR
untranslated region
RT-PCR
reverse transcription PCR

Keywords

Orphan receptor
GPR34
G-protein-coupled receptor
Genomic organization
Promoter
Translation start

Cited by (0)

Sequence data from this article have been deposited with the GenBank Data Library under Accession Nos. DQ_106398–DQ_106402DQ_106398DQ_106399DQ_106400DQ_106401DQ_106402 (human ESTs), DQ_103764–DQ_103767DQ_103764DQ_103765DQ_103766DQ_103767 (mouse ESTs), and DQ_106403 (bonobo GPR34).