{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T06:40:29Z","timestamp":1790836829451,"version":"4.1.0"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"11","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1996,5,28]]},"abstract":"<jats:p>The hepatitis B virus X protein (HBx) sequence (154 aa) has been divided into six regions (A-F) based on its sequence homology with X proteins of other mammalian hepadnaviruses. Regions A, C, and E are more conserved and include all the four conserved cysteines (C7, C61, C69, and C137). To localize the regions of HBx important for transactivation, a panel of 10 deletion mutants (X5-X14) and 4 single point mutants (X1-X4), each corresponding to a conserved cysteine residue, was constructed by site-directed mutagenesis. A HBx-specific monoclonal antibody was developed and used to confirm the expression of mutants by Western blot. Transactivation property of the HBx mutants was studied on Rous sarcoma virus-long terminal repeat (RSV-LTR) in transient transfection assays. We observed that deletion of the most conserved region A or substitution of the N-terminal cysteine (C7) had no effect on transactivation. Deletion of the nonconserved regions B or F also had no deleterious effects. Deletions of regions C and D resulted in a significant loss of function. Substitution of both C61 and C69 present in region C, caused almost 90% loss of activity that could be partially overcome by transfecting more expression plasmid. The fully conserved 9 amino acid segment (residues 132 to 140) within region E including C137 appeared to be crucial for its activity. Finally, a truncated mutant X15 incorporating only regions C to E (amino acids 58-140) was able to stimulate the RSV-LTR quite efficiently, suggesting a crucial role played by this domain in transactivation function.<\/jats:p>","DOI":"10.1073\/pnas.93.11.5647","type":"journal-article","created":{"date-parts":[[2002,7,26]],"date-time":"2002-07-26T10:43:20Z","timestamp":1027680200000},"page":"5647-5652","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":121,"title":["A truncated mutant (residues 58-140) of the hepatitis B virus X protein retains transactivation function."],"prefix":"10.1073","volume":"93","author":[{"given":"V","family":"Kumar","sequence":"first","affiliation":[{"name":"Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N","family":"Jayasuryan","sequence":"additional","affiliation":[{"name":"Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R","family":"Kumar","sequence":"additional","affiliation":[{"name":"Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1996,5,28]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.93.11.5647","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T14:00:49Z","timestamp":1649858449000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.93.11.5647"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1996,5,28]]},"references-count":0,"journal-issue":{"issue":"11","published-print":{"date-parts":[[1996,5,28]]}},"alternative-id":["10.1073\/pnas.93.11.5647"],"URL":"https:\/\/doi.org\/10.1073\/pnas.93.11.5647","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1996,5,28]]},"assertion":[{"value":"1996-05-28","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}