title: Detection of an element of the SV40 late promoter in vectors used for expression studies in COS cells.
abstract: Plasmids containing hepatitis B virus (HBV) DNA and a 232-bp SV40 DNA fragment encoding the origin of replication were constructed. When introduced by transfection into COS cells, these plasmids directed the synthesis of hepatitis B surface antigen. S1 mapping of the mRNAs covering the S gene showed that transcriptional initiation was promoted by the interaction of HBV sequences with an SV40 promoter element: transcription started on HBV DNA but had several properties of SV40 late transcription. The detection of a promoter element in an SV40 origin fragment commonly used in the COS system is important for the interpretation of data deriving from expression studies in COS cells.
mesh_terms: D000818:Animals; D002460:Cell Line; D004274:DNA, Recombinant; D004279:DNA, Viral / Q000235:genetics; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics; D009876:Operon; D010957:Plasmids; D013539:Simian virus 40 / Q000235:genetics*
chemical_list: D004274:DNA, Recombinant; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens