[Higher expression levels of alternatively spliced pX mRNA in human T lymphotropic virus type I (HTLV-I) asymptomatic carriers positive for antibodies to p40tax protein].
We cloned and sequenced complementary DNA (cDNA) of human T lymphotropic virus type I (HTLV-I) pX gene mRNA expressed in peripheral blood lymphocytes of asymptomatic carriers and searched for a possible correlation between HTLV-I pX mRNA expression levels to viral load and anti-p40tax status. Nine cDNA clones had four alternatively spliced forms of mRNA, three forms were identical to the reported cDNA sequences. One cDNA clone contained a novel splicing acceptor site, thereby indicating an unidentified form of pX mRNA, termed as pX delta 17 delta 37. These results, together with previous observations, suggest that HTLV-I has complex pattern of splicing. The expression levels of the five pX mRNAs, pX, pX delta 17, p21rex, orf II, and pX delta 17 delta 37, were examined in twenty-one asymptomatic carriers. Alternatively spliced pX mRNA species were detected in all the carriers. Semiquantitation of pX mRNAs revealed that pX and pX delta 17 were the dominant mRNA species among alternatively spliced pX mRNA. All pX mRNAs but the orf II message correlated with amounts of proviral DNA significantly (p < 0.05). The levels of proviral DNA and mRNAs were significantly higher in anti-p40tax positive carriers than in negative ones. These observations suggest that the alternatively spliced pX mRNAs are expressed ubiquitously in the peripheral blood lymphocytes of HTLV-I asymptomatic carriers with complex pattern of splicing and that the presence of anti-p40tax may be a marker for a higher viral load and viral replication levels in HTLV-I asymptomatic carriers. Our observations may explain previous finding that the carriers rate is higher in the offspring of anti-p40tax positive mothers than those of anti-p40tax negative mothers.
Hirata
M
M
Department of General Medicine, Kyushu University Hospital, Fukuoka.
D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D002353:Carrier State; D015480:Deltaretrovirus Antibodies / Q000032:analysis*; D005260:Female; D016356:Gene Products, tax / Q000276:immunology*; D016355:Genes, pX; D015490:HTLV-I Infections / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis*
D015480:Deltaretrovirus Antibodies; D016356:Gene Products, tax; D012333:RNA, Messenger