Analysis of the genes encoding the mast cell function-associated antigen and its alternatively spliced transcripts
Bocek, P.; Guthmann, M.D.; Pecht, I.
Journal of Immunology 158(7): 3235-3243
1997
ISSN/ISBN: 0022-1767 PMID: 9120279 Document Number: 476459
The mast cell function-associated antigen (MAFA) is a C-type lectin that inhibits the Fc epsilon RI stimulation-induced mast cell secretory response. The present study showed that MAFA was encoded by a single-copy gene that spanned 13 kb in the rat genome and was composed of 5 exons. Three separate exons encoded the carbohydrate recognition domain of the MAFA, defining its close homology to the genes of CD23, CD69, CD72, NKR-P1 and Ly49. Functional analysis of the 5' flanking region of the gene revealed that a cell type-specific promoter was located within the first 664 bp upstream of the transcription origin. The promoter lacked any obvious TATA box and drove gene transcription originating from multiple start sites. Examination for possible polymorphism of the MAFA transcripts revealed 2 transcripts, generated by alternative splicing. Deletion of the transmembrane exon in one of them did not result in a frameshift and would, upon translation, give rise to a soluble MAFA molecule. Splicing of 2 exons in a second transcript resulted in a new reading frame encoding a putative protein containing MAFA's cytoplasmic domain. The transcription of the MAFA gene was detected in normal rat lungs, where transmembrane and soluble MAFA appeared to be expressed. Lung immunohistochemical analysis further suggested that MAFA expression was restricted to mast cells.