The X gene of hepatitis B virus shows a high level stimulation of the Rous sarcoma virus long terminal repeat in the methylotropic yeast, Pichia pastoris.
In order to study the transactivational property of the X gene in the methylotropic yeast Pichia pastoris, a Rous sarcoma virus-chloramphenicol acetyltransferase (RSV-CAT) cassette was co-transformed and integrated into the host yeast strain as a reporter which showed an overwhelming CAT activity. Immunoprecipitation of the yeast cell extracts with an X-specific monoclonal antibody, however, showed a low level expression of the X gene. Therefore besides a trans-effect of the X protein, the enhanced reporter activity could be a manifestation of a cis-effect of the X gene sequences also. Therefore, unlike the transactivation studies with X gene in animal cells where limited functional activity is observed, P. pastoris appears to be an excellent system to study cis- and trans-aspects of gene regulation by the X gene.
Lal
S K
SK
Virology Group, International Centre for Genetic Engineering & Biotechnology, Aruna Asaf Ali Marg, New Delhi, India. sunillal@icgeb.res.in
Kumar
V
V
D001358:Avian Sarcoma Viruses / Q000235:genetics*; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D005814:Genes, Viral; D006515:Hepatitis B virus / Q000235:genetics*; D009154:Mutation; D010843:Pichia / Q000821:virology*; D020079:Terminal Repeat Sequences / Q000235:genetics*; D015533:Transcriptional Activation; D014170:Transformation, Genetic
D015500:Chloramphenicol O-Acetyltransferase