The Journal of Immunology, Vol 158, Issue 8 3561-3564, Copyright © 1997 by American Association of Immunologists

CUTTING EDGE

Alternate splicing of mouse fusin/CXC chemokine receptor-4: stromal cell-derived factor-1alpha is a ligand for both CXC chemokine receptor- 4 isoforms

M Heesen, MA Berman, UE Hopken, NP Gerard and ME Dorf
Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

Inspection of the intron splice junction of the mouse chemokine receptor fusin/CXC chemokine receptor R-4 (CXCR-4) revealed a potential in-frame alternative splice site in the region encoding the N-terminal ectodomain of the receptor. Both predicted splice products were detected by reverse transcriptase-PCR. Cell lines of T lymphocyte, B lymphocyte, and macrophage lineage, plus populations of elicited peritoneal exudate cells, thymocytes, and astrocytes coexpressed mRNA for both isoforms. The full length cDNA of the shorter alternate splice product, termed CXCR-4B, was cloned from peritoneal exudate cell RNA. Chinese hamster ovary cells transfected with either isoform, CXCR-4A or CXCR-4B, responded to stromal cell-derived factor-1alpha with a rise in intracellular calcium. Both alternate splice products are therefore functional stromal cell-derived factor-1 alpha receptors.