Isolation and characterization of the rat β-subunit gene of the high affinity receptor for immunoglobulin E

The high affinity receptor for IgE, which mediates allergic reactions, is found exclusively on mast cells, basophils and epidermal Langerhans cells. It is composed of an α, β and two γ-polypeptide chains, inserted as a complex into the plasma membrane. The α and β-subunits are produced only by these cell types. This work describes the isolation and characterization of the gene which encodes the rat P-subunit. The single copy gene spans a 9 kbp region of DNA and is composed of seven exons and six introns. Transcriptional initiation begins from a single site, which is preceded by a very unique, putative transcriptional consensus sequence, the GATA box. Analysis of the 5'-region, upstream of exon 1, also reveals a unique sequence bias and a collection of repeating elements, suggesting several other potential transcriptional cis-control elements. The origins of the two, previously reported, different β-subunit transcripts result from the same start site of this gene, but use an alternative RNA processing mechanism involving exon 3.