Open AccessTwo lck transcripts containing different 5' untranslated regions are present in T cells.
Author(s) -
A F Voronova,
H T Adler,
Bartholomew M. Sefton
Publication year - 1987
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.7.12.4407
Subject(s) - biology , untranslated region , microbiology and biotechnology , messenger rna , promoter , three prime untranslated region , rna splicing , five prime untranslated region , exon , murine leukemia virus , virology , gene , gene expression , rna , virus , genetics
p56lck is a new member of the src family of cellular tyrosine protein kinases. It is expressed constitutively at a low level in normal T cells and at an elevated level in the LSTRA and Thy19 Moloney murine leukemia virus-induced thymoma cell lines. It is possible that the expression of p56lck at an elevated level contributes to the transformation of these thymoma cells. The structure of the mRNAs encoding p56lck was examined by using an RNase protection assay. Both a chimeric lck mRNA containing the 5' untranslated region of Moloney virus mRNA and a normal lck mRNA were found in Thy19 and LSTRA cells. The chimeric lck transcript was 4- to 10-fold more abundant than the normal transcript. Transcription arising from a viral promoter is therefore responsible for the elevated levels of lck mRNA in these two cell lines. Surprisingly, uninfected murine T cells were also found to contain lck transcripts with differing 5' untranslated regions. One species of mRNA was colinear with the region of the chromosome just upstream of the initiation codon for p56lck. The other appeared to arise through splicing of an unidentified 5' untranslated exon to a sometimes cryptic splice acceptor just upstream of the region encoding p56lck. These data suggest that lck is expressed through the use of at least two different promoters. The promoters could be subject to different forms of regulation.