Characterization of the RDC1 gene which encodes the canine omolog of a proposed human VIP receptor Expression does not correlate with an increase in VIP binding sites

[摘要]

We have isolated a portion of the canine gene encoding the orphan receptor RDC1 [1]. The complete coding sequence is contained in a single exon, and an intron divides the 5′ untranslated region of RDC1 mRNA. The RDC1 protein is 94% homologous to the gene product of GPRN1, which has been proposed to serve as a VIP receptor when expressed in CHO-K1 and COS-7 cells (Sreedharan, S.P. et al. (1991) Proc. Natl. Acad. Sci. USA 88, 4986–4990). Northern analysis indicates that CHO-K1 cells endogenously express a 2.1 kb RDC1 mRNA. However, while CHO-K1 cells possess detectable low affinity [¹²⁵I]VIP binding sites, VIP binding is not altered in membranes of CHO-K1 cells expressing varying amounts of the RDC1 gene construct. Further, endogenous VIP binding is not increased by transient expression of RDC1 in COS-7 cells. Taken together, the data suggest that RDC1 is not a canine homolog of the proposed VIP receptor.

[学科分类] 生物化学/生物物理

[关键词] RDC1;VIP receptor;Receptor expression;Receptor cloning;G-protein;VIP;vasoactive intestinal peptide;DMEM;Dulbecco's modified Eagle medium;BSA;bovine serum albumin;fMLP;N-formyl-Met-Leu-Phe;IL-8;interleukin-8;1×SSPE;0.18 M NaCl;0.01 M NaH2PO4;pH 7.1;0.1 mM EDTA;WT;wild-type (untransfected) cells;FBS;fetal bovine serum