An HLA-E-specific oligonucleotide probe was used
to study the expressioonf HLA-E. This probed etects
two HLA-E transcripts, 1.8 and 2.7 kb in size, which
are present in varying ratios in allt issues and cell
lines investigated. We demonstrate that alternative
poly(A) site usage accounts for the differential regulation
of the two HLA-E mRNA species. Sequence
analysis of three cDNA clones, representing the two
transcripts of HLA-E, and of anH LA-E gene encoded
by cosmid cd3.14, revealed identity of gene and
cDNA in the 3’ untranslated region. S1 nuclease
protection assays confirmed that the two HLA-E
transcripts are not alternative splicing products.
Introduction of cd3.14, together with human ,&m
into the murine myeloma cell line P3X63-Ag8.653,
resulted in a cell surface expresosf ioan HLA-class
I heavy chain detectablbey indirect immunofluorescence
whereas transfection into the humBaznr n expressing
mouse L cell line, 527 was negative with
regard to cell surface expressionC. ell surface labeling
of transfectants and immunoprecipitation with
a monomorphic HLA class I-specific antibodyo r an
antibody against human &m confirmed the presence
of an HLA-E H chain on the cell surface. These
results indicate that the HLA-E gene codes for a
class I H chain that can be expressed on the cell
surface
