Expression of calpain II gene in human hematopoietic system cells infected with human T-cell leukemia virus type I.
We examined the distribution of calpains I and II in human hematopoietic system cell lines by Western and Northern blot analyses and enzyme activity assay. Expression of calpain I, a low Ca(2+)-requiring cysteine protease, was observed in all human T-cell lines tested. By contrast, expression of calpain II, a high Ca(2+)-requiring form, in human T-cells was closely correlated with human T-cell leukemia virus type I (HTLV-I) infection, which is known to result in the expression of adult T-cell leukemia-associated antigens, interleukin-2 (IL-2) receptor alpha, and Ca(2+)-dependent cell proliferation. Specific expression of calpain II in HTLV-I-infected cells occurred at the mRNA level. Furthermore, expression of calpain II in human natural killer-like cells was augmented by HTLV-I pX gene transfection. In HTLV-I-infected cells, the trans-acting transcriptional activation of the long terminal repeat and control elements for the IL-2 receptor alpha, c-fos, and granulocyte-macrophage colony-stimulating factor genes by the Tax from the pX gene is already known. Our results suggest that the similar trans-activation occurs to the calpain II gene in HTLV-I-infected hematopoietic system cells.
Adachi
Y
Y
Institute for Virus Research, Kyoto University, Japan.
Kitahara-Ozawa
A
A
Sugamura
K
K
Lee
W J
WJ
Yodoi
J
J
Maki
M
M
Murachi
T
T
Hatanaka
M
M
D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002154:Calpain / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D016355:Genes, pX; D015490:HTLV-I Infections / Q000235:genetics*; D006412:Hematopoietic Stem Cells / Q000382:microbiology*; D006801:Humans; D066298:In Vitro Techniques; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured
D002135:Calcium-Binding Proteins; D012333:RNA, Messenger; C033668:calpastatin; D002154:Calpain