Molecular and genomic characterization of human DLEC, a novel member of the C-type lectin receptor gene family preferentially expressed on monocyte-derived dendritic cells

We have identified a novel gene encoding a protein designated DLEC (dendritic cell lectin), which is a type II membrane glycoprotein of 213 amino acids and belongs to the human calcium-dependent (C-type) lectin family. The cytoplasmic tail of DLEC lacks consensus signaling motifs and its extracellular region shows a single carbohydrate recognition domain (CRD), closest in homology to the dendritic cell immunoreceptor (DCIR) CRD. The DLEC gene has been localized linked to DCIR on the telomeric region of the NK gene complex. RT-PCR and Northern blot analyses show that DLEC mRNA is preferentially expressed in monocyte-derived dendritic cells.

Molecular characterization of two novel alternative spliced variants of the KLRF1 gene and subcellular distribution of KLRF1 isoforms

The killer cell lectin-like receptor (KLR) family is formed by type II transmembrane glycoproteins with a single extracellular C-type lectin-like domain (CTLD). Some of these glycoproteins are involved in the regulation of natural killer cell activity. Recently, we have described the molecular characterization of the KLRF1 gene and the existence of one alternative spliced form, lacking the stalk region of the extracellular domain. In this work we describe two novel KLRF1 alternative spliced variants coding for truncated proteins lacking the CTLD. In addition, we present the biochemical analysis of the KLRF1 protein and the subcellular distribution of all KLRF1 isoforms expressed in heterologous transfectants.

Cloning of human DECTIN-1, a novel C-type lectin-like receptor gene expressed on dendritic cells

We identified a new Ca2+-dependent lectin-like receptor gene, DECTIN-1 (HGMW-approved symbol CLECSF12), the human orthologue of mouse Dectin-1, coding for a putative type II transmembrane glycoprotein with an extracellular C-type lectin-like domain. The gene structure and two alternative spliced forms of DECTIN-1 are described. The DECTIN-1 gene was localized in the natural killer gene complex on human Chromosome 12p12.3-p13.2, between OLR1 and CD94 (position 21.8 cM on the genetic map). The DECTIN-1 gene is highly expressed at the mRNA level in dendritic cells and is not further up-regulated during the maturation of these cells with tumor necrosis factor-alpha. The DECTIN-1 gene therefore represents a novel human member of the C-type lectin-like receptor gene family preferentially expressed in dendritic cells.

A sequence-ready physical map of the region containing the human natural killer gene complex on chromosome 12p12.3-p13.2

We developed a sequence-ready physical map of a part of human chromosome 12p12.3-p13.2 where the natural killer gene complex (NKC) is located. The NKC includes a cluster of genes with structure similar to that of the Ca(2+)-dependent lectin superfamily of glycoproteins that are expressed on the surface of most natural killer (NK) cells and a subset of T cells. These killer cell lectin-like receptors (KLR) are involved in NK target cell recognition, leading to activation or inhibition of NK cell function. We used a number of sequence-tagged site (STS) markers from this region to screen two large insert bacterial artificial chromosome (BAC) libraries and a bacteriophage P1-derived (PAC) chromosome library. The clones were assembled into contiguous sets by STS content analysis. The 72-BAC and 11-PAC contig covers nearly 2 Mb of DNA and provides an average marker resolution of 26 kb. We have precisely localized 17 genes, 5 expressed sequence tags, and 49 STSs within this contig. Of this total number of STS, 30 are newly developed by clone-end sequencing. We established the order of the genes as tel-M6PR-MAFAL (HGMW-approved symbol KLRG1)-A2M-PZP-A2MP-NKRP1A (HGMW-approved symbol KLRB1)-CD69-AICL (HGMW-approved symbol CLECSF2)-KLRF1-OLR1-CD94 (HGMW-approved symbol KLRD1)-NKG2D (HGMW-approved symbol D12S2489E)-PGFL-NKG2F (HGMW-approved symbol KLRC4)-NKG2E (HGMW-approved symbol KLRC3)-NKG2A (HGMW-approved symbol KLRC1)-LY49L (HGMW-approved symbol KLRA1)-cen. This map would facilitate the cloning of new KLR genes and the complete sequencing of this region.

Human KLRF1, a novel member of the killer cell lectin-like receptor gene family: molecular characterization, genomic structure, physical mapping to the NK gene complex and expression analysis

The human NK gene complex localized on chromosome 12p12.3 - p13.2 codes for several lectin-like receptor genes expressed by NK cells as well as by other hematopoietic cells. In this study, by using the expressed sequence tag database we identified a novel receptor gene, designated as killer cell lectin-like receptor, subfamily F, member 1 (KLRF1), encoding a putative type II transmembrane glycoprotein. The KLRF1 gene has been localized on the high-resolution physical map of chromosome 12p. The genomic structure of the KLRF1 gene and the existence of one spliced variant are also described. KLRF1 was expressed at the mRNA level in peripheral blood leukocytes, activated NK cells, monocytes and NK and myeloid cell lines. The presence of two immunoreceptor tyrosine-based inhibitory-like motifs within the cytoplasmic tail of KLRF1 suggests an inhibitory role in NK cell and monocyte activity.

The human natural killer gene complex is located on chromosome 12p12-p13

Natural killer (NK) cells preferentially express several type II glycoproteins of the calcium-dependent lectin superfamily. The genes coding for these molecules are clustered on the distal mouse chromosome 6 and on the rat chromosome 4 in a region designated the NK gene complex. To date, no definite evidence of the presence of a NK gene complex has been found in humans. Here we report the assignment by fluorescence in situ hybridization of the CD94 gene to human chromosome 12p12-p13, in the same region where the CD69 and NKG2A genes had been previously mapped. In addition, using a yeast artificial chromosome contig spanning this region we determined that the human CD94, NKG2A, NKG2C, NKG2E, and NKR-P1A (NKR) genes map to the short arm of chromosome 12. The distal to proximal position of these loci are: NKR- CD69 - CD94/NKG2A/NKG2C/NKG2E. These data demonstrate the existence of a human NK gene complex located within a 5.6 cM interval flanked by the genetic markers D12S397 and D12S89. The physical distance spanned by the NK gene complex in humans ranges between 0.7 and 2.4 megabases.