DIFFERENTIAL EXPRESSION OF ALTERNATIVELY SPLICED PX MESSENGER-RNAS INHTLV-I-INFECTED CELL-LINES

Human T cell leukemia/lymphotropic virus (HTLV) is a complex 9 kb huma n retrovirus with at least eight alternatively spliced mRNAs expressed from the 3' or pX region of the genome. These mRNAs allow for the exp ression of novel proteins from the previously recognized pX open readi ng frames I and II in addition to Tax, Rex and p21(rex) encoded from o rf III and IV. These alternatively spliced messages have been using re verse-transcriptase polymerase chain (RT/PCR) amplification in HTLV-I- transformed T cell lines as well as in peripheral blood mononuclear ce lls (PBMC) from infected patients with and without disease. To gain in sight into the role of these alternatively spliced mRNAs in pathogenes is, we developed a semi-quantitative non-PCR-based RNase protection as say to detect and quantitate their presence in HTLV-I-infected cells. Analysis of RNA from HTLV-I-infected cells established from patients w ith adult T cell leukemia (ATL) as well as tropical spastic paraparesi s/HTLV-I-associated myelopathy (TSP/HAM) and both IL-2-dependent and I L-2-independent HTLV-I-infected cell lines by RNase protection has con firmed the existence of all of the alternatively spliced messages in e ach cell line analyzed. However, the relative quantity of each message was significantly different among these lines suggesting that splice site utilization is an important viral regulatory pathway.