Genomic structure and cDNA analysis of two C-type lectin receptors, DCIR and DCAR, in duck (Anas platyrhynchos)

Two C-type lectin immunoreceptor genes were identified in a previous expressed sequence tag project from duck spleen. These sequences were used to screen duck genomic and cDNA libraries. A genomic clone was fully sequenced, containing one dendritic cell immunoreceptor (DCIR) gene and two dendritic cell activating receptor (DCAR) genes arranged in tandem order. The duck DCIR gene featured an immunoreceptor tyrosine-based inhibitory motif (ITIM) in the cytoplasmic domain. The DCAR1 gene carried a stop codon in the carbohydrate recognition domain. Since no transcript was found for DCAR1, it was considered to be a pseudogene. cDNA clones matching the DCAR2 gene were identified and had features typical of activating receptors. Alternatively spliced transcripts were identified for both DCIR and DCAR2. These inhibitory and activating receptors may be involved in the regulation of duck antigen presenting cells.