Altered interleukin-2 receptor alpha-chain is expressed in human T-cell leukaemia virus type-I-infected T-cell lines and human peripheral blood mononuclear cells of adult T-cell leukaemia patients through an alternative splicing mechanism.
A polymerase chain reaction (PCR) method was used to detect the interleukin-2 receptor alpha-chain (IL-2R alpha) chain which lacks the conventional transmembrane (TM) domain in mRNA from human T-cell leukaemia virus type-I (HTLV-I)-infected cell lines or peripheral blood mononuclear cells (PBMC) isolated from adult T-cell leukaemia (ATL) patients. Primer pairs encompassing the TM domain were selected to generate a 357-base pair (bp) fragment. A 146-bp PCR product was observed consistently in addition to the target 357-bp PCR product in mRNA from HTLV-I-infected cell lines, such as MT-1, MT-2, MT-4 and in PBMC isolated from ATL patients. However, this 146-bp PCR product was undetectable in HTLV-I-negative cell lines. The product was also detected in PBMC from normal individuals if activated in vitro with phytohaemagglutinin but not without stimulation. DNA sequence analyses revealed that exons from 5 to 7, which define a 211-bp region containing the conventional TM domain, were deleted in the 146-bp PCR product. The C-terminal amino acid sequence starting from Gly174 of the 211-bp-deleted molecule was distinct from that of conventional IL-2R alpha as a result of an altered reading frame. We identified a 45000 MW peptide generated from IL-2R alpha mRNA through this exon skip in cell lysate of MT-1 and MT-2 by Western blot analyses using an antibody raised against the peptides specific to an altered IL-2R alpha. Our results indicate that an altered IL-2R alpha chain is expressed in HTLV-I-infected T lymphocytic cell lines and in ATL patients.
Horiuchi
S
S
Department of Microbiology, Faculty of Medicine, Tokyo Medical and Dental University, Japan.
Koyanagi
Y
Y
Tanaka
Y
Y
Waki
M
M
Matsumoto
A
A
Zhou
Y W
YW
Yamamoto
M
M
Yamamoto
N
N
D000328:Adult; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D001483:Base Sequence; D015153:Blotting, Western; D015870:Gene Expression; D015490:HTLV-I Infections / Q000276:immunology*; D006801:Humans; D015458:Leukemia, T-Cell / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D015375:Receptors, Interleukin-2 / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D015375:Receptors, Interleukin-2