Multiple products derived from two CCL4 loci: high incidence of a new polymorphism in HIV+ patients.

Human CCL4/macrophage inflammatory protein (MIP)-1beta and CCL3/MIP-1alpha are two highly related molecules that belong to a cluster of inflammatory CC chemokines located in chromosome 17. CCL4 and CCL3 were formed by duplication of a common ancestral gene, generating the SCYA4 and SCYA3 genes which, in turn, present a variable number of additional non-allelic copies (SCYA4L and SCYA3L1). In this study, we show that both CCL4 loci (SCYA4 and SCYA4L) are expressed and alternatively generate spliced variants lacking the second exon.