Cloning and genomic localization of the murine LPS-induced CXC chemokine (LIX) gene, Scyb5.

LPS-induced CXC chemokine (LIX) is a murine chemokine similar to two human chemokines, ENA-78 (CXCL5) and GCP-2 (CXCL6). To clarify the relationship of LIX to human ENA-78 and GCP-2, we cloned and mapped the LIX gene. The organization of the LIX gene ( Scyb5) is similar to those of the human ENA-78 ( SCYB5) and GCP-2 ( SCYB6) genes. The intron-exon boundaries of the three genes are exactly conserved, and the introns have similar sizes. The first 100 bp of the 5' flanking regions are highly similar, with conserved NF-kappaB and GATA sites in identical positions in all three genes. Further 5', the Lix flanking region sequence diverges from those of ENA-78 and GCP-2, which remain highly similar for 350 bp preceding the start sites. Using a (C57BL/6 J x Mus spretus) F1 x C57BL/6J backcross panel, Lix was mapped to a locus near D5Ucla5 at 49.0 cM on Chromosome (Chr) 5. Mapping with the T31 radiation hybrid panel placed Lix between D5Mit360 and D5Mit6. Physical maps of the CXC chemokine clusters on murine Chr 5 and human Chr 21 were constructed using the Celera mouse genome database and the public human genome database. The sequence and mapping data suggest that the human ENA78-PBP-PF4 and GCP2- psi PBP-PF4V1 loci arose from an evolutionarily recent duplication of an ancestral locus related to the murine Lix-Pbp-Pf4 locus.