Sequence variation of a novel heptahelical leucocyte receptor through alternative transcript formation.

摘要: Chemoattractants, including chemokines such as interleukin 8 (IL-8) and related proteins, activate leucocytes via seven-transmembrane-domain G-protein-coupled receptors. A cDNA for a novel receptor of this kind consisting 327 amino acids was isolated from human blood monocyte library. The polypeptide, termed monocyte-derived 15 (MDR15), is an alternative form the Burkitt's lymphoma 1 (BLR1) encoded by [Dobner, Wolf, Emrich Lipp (1992) Eur. J. Immunol. 22, 2795-2799]. MDR15 BLR1 cDNAs differ in 5' region, where open reading frame shorter 45 codons. Southern-blot analysis indicates that two transcripts are same gene. Northern-blot using probe hybridizes with both mRNAs demonstrated high-level expression chronic B-lymphoid leukaemia non-Hodgkin's cells and, to lesser extent, peripheral monocytes lymphocytes. Reverse transcription-PCR studies MDR15- BLR1-specific primers showed similar levels receptors RNA positive analysis. have high structural similarity IL-8 (about 40% acid identity) other chemokines. However, none series radiolabelled (IL-8, NAP-2, GRO alpha, PF4, IP10, MCP-1, MCP-2, MCP-3, I-309, RANTES MIP-1 alpha) ligands (C3a leukotriene B4) bound Jurkat transfectants stably expressed either or mRNA. fact on show marked sequence chemokine suggests existence yet unidentified Alternative transcript formation affecting 5'-terminal part coding region may be way modify ligand-binding selectivity.