title: Conserved organization of the ILT/LIR gene family within the polymorphic human leukocyte receptor complex.
abstract: The human leukocyte receptor complex (LRC) at Chromosome 19q13.4 encodes Ig superfamily proteins which regulate the function of various hematopoietic cell types. We investigated characteristics of the Ig-like transcript (ILT)/leukocyte Ig-like receptor (LIR) group of LRC genes in comparison with the other major LRC loci encoding the killer cell Ig-like receptors (KIRs). In direct contrast to KIR genes, the ILT/LIR loci of ethnically diverse individuals did not display haplotypic variations in gene number. Investigation of gene expression identified novel cDNA sequences related to the ILT2/LIR1, ILT4/LIR2, ILT3/LIR5, and ILT7 loci, while phylogenetic analysis revealed two distinct lineages of ILT/LIR genes. These two lineages differ in both the nature and extent of their sequence polymorphism. The presence of certain transcription factor-related motifs in the 5' untranslated region of ILT/LIR cDNAs correlates with the specific cell types in which particular ILT/LIR genes are expressed. Although extensive gene duplications and conversion events have apparently forged the LRC, our results indicate striking conservation in the organization of the ILT/LIR genes when compared with the related and closely linked KIR genes. This suggests the evolutionary maintenance of a significant function consistent with the cellular distribution of the ILT/LIR proteins.
authors.affiliation: Department of Structural Biology, Stranford University School of Medicine, CA 94305, USA. neil.young@nds.ox.ac.uk
authors.forename: N T
authors.initials: NT
authors.lastname: Young
authors.forename: F
authors.initials: F
authors.lastname: Canavez
authors.forename: M
authors.initials: M
authors.lastname: Uhrberg
authors.forename: B P
authors.initials: BP
authors.lastname: Shum
authors.forename: P
authors.initials: P
authors.lastname: Parham
mesh_terms: D001483:Base Sequence; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006239:Haplotypes; D006801:Humans; D007962:Leukocytes / Q000276:immunology*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D011110:Polymorphism, Genetic; D011971:Receptors, Immunologic / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D011971:Receptors, Immunologic