Carbohydrate-binding specificities of mouse ficolin A, a splicing variant of ficolin A and ficolin B and their complex formation with MASP-2 and sMAP
We previously cloned a novel human lectin, designated P35, with both collagen-like and fibrinogen-like domains. P35 recognizes GlcNAc residues and is opsonic toward microorganisms. The overall structure of P35 closely resembles those of two pig ficolins that are putative TGF-beta 1-binding proteins. In this study, we analyzed the exon-intron structure and chromosomal location of the P35 gene as well as its structural relationship to splicing variants. In addition, we isolated another distinct genomic clone corresponding to the upstream region of a P35-related gene that has an exon organization closely resembling that of the P35 gene. The sequences of exons in the P35-related gene were identical to the cDNA sequence reported for "human ficolin." Northern blotting revealed that the P35 gene is expressed mainly in liver, whereas the P35-related gene is expressed in lung and peripheral blood leukocytes, demonstrating tissue-specific expression of these two genes. Both genes were assigned to a closely related region of chromosome 9 at 9q34.