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Two lck transcripts containing different 5' untranslated regions are present in T cells.
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138.
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.
PMID: 3501824 [PubMed - indexed for MEDLINE]
PMCID: PMC368124
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Cited by 16 PubMed Central articles
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Lck domains differentially contribute to pre-T cell receptor (TCR)- and TCR-alpha/beta-regulated developmental transitions.
Lin K, Longo NS, Wang X, Hewitt JA, Abraham KM.
J Exp Med. 2000 Feb 21; 191(4):703-16.
[J Exp Med. 2000]
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Interleukin (IL) 15/IL-T production by the adult T-cell leukemia cell line HuT-102 is associated with a human T-cell lymphotrophic virus type I region /IL-15 fusion message that lacks many upstream AUGs that normally attenuates IL-15 mRNA translation.
Bamford RN, Battiata AP, Burton JD, Sharma H, Waldmann TA.
Proc Natl Acad Sci U S A. 1996 Apr 2; 93(7):2897-902.
[Proc Natl Acad Sci U S A. 1996]
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Mutation of a site of tyrosine phosphorylation in the lymphocyte-specific tyrosine protein kinase, p56lck, reveals its oncogenic potential in fibroblasts.
Amrein KE, Sefton BM.
Proc Natl Acad Sci U S A. 1988 Jun; 85(12):4247-51.
[Proc Natl Acad Sci U S A. 1988]
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