Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Two discrete events, human T-cell leukemia virus type I Tax oncoprotein expression and a separate stress stimulus, are required for induction of apoptosis in T-cells | Retrovirology BioMed Central Research Open Access Two discrete events human T-cell leukemia virus type I Tax oncoprotein expression and a separate stress stimulus are required for induction of apoptosis in T-cells Takefumi Kasai and Kuan-Teh Jeang Address Laboratory of Molecular Microbiology NIAID National Institutes of Health Bethesda Maryland 20892-0460 USA Email Takefumi Kasai - tkasai@ Kuan-Teh Jeang - kj7e@ Corresponding author Published 06 May 2004 Received 23 April 2004 Accepted 06 May 2004 Retrovirology 2004 1 7 This article is available from http content 1 1 7 2004 Kasai and Jeang licensee BioMed Central Ltd. This is an Open Access article verbatim copying and redistribution of this article are permitted in all media for any purpose provided this notice is preserved along with the article s original URL. Abstract Background It is poorly understood why many transforming proteins reportedly enhance both cell growth transformation and cell death apoptosis . At first glance the ability to transform and the ability to engender apoptosis seem to be contradictory. Interestingly both abilities have been widely reported in the literature for the HTLV-I Tax protein. Results To reconcile these apparently divergent findings we sought to understand how Tax might cause apoptosis in a Jurkat T-cell line JPX-9. Tax expression can be induced equally by either cadmium Cd or zinc Zn in JPX-9 cells. Surprisingly when induced by Zn but not when induced by Cd Tax-expression produced significant apoptosis. Under our experimental conditions Zn but not Cd induced SAPK stress activated protein kinase JNK Jun kinase activation in cells. We further showed that transient over-expression of Tax-alone or Jun-alone did not induce cell death. On the other hand co-expression of Tax plus Jun did effectively result in apoptosis. Conclusion We propose that Tax-expression alone in a T-cell background insufficiently accounts for apoptosis. On
