The mouse Lect2 gene: cloning of cDNA and genomic DNA, structural characterization and chromosomal localization.

We previously purified bovine leukocyte cell-derived chemotaxin 2 (LECT2) as a 16 kDa-secreted protein with a neutrophil chemotactic activity. LECT2 protein is thought to be multifunctional, since it was recently found to be identical to chondromodulin-II, a growth stimulator of chondrocyte cells. We report here the cloning and structural analysis of mouse Lect2 cDNAs and genomic DNA, and chromosomal mapping. Two types of mouse Lect2 cDNAs were cloned: one encoded the mouse counterpart of human and bovine LECT2 proteins, and the other encoded a queer type LECT2 protein whose amino-acid sequence in the carboxy terminus was different from that of the normal type LECT2 protein. The mouse Lect2 gene spanned approx. 8 kb and consisted of five exons and four introns. The genomic organization revealed that two type transcripts arose by an alternative splicing event involving exon 4. A primer extension analysis revealed that several transcription initiation sites occurred within 60-210 nucleotides upstream from the translation initiation codon. The mouse Lect2 gene was mapped to a region adjacent to D13Mit13, D13Mit21 and Il-9 on chromosome 13 by interspecific backcross mapping.