title: [Development of a new system for selection of A. foetidus transformed with foreign genes by using thymidine kinase gene as a marker and expression of HBsAg gene in A. foetidus].
abstract: A new system for selection of transformed Aspergillus foetidus was reported. In this system, TK- A. foetidus which were constructed by homologous recombination of mutated TK gene of vaccinia virus with TK gene of A. foetidus were screened by adding BUdR in agar plates. Conditions for screen of TK+ A. foetidus strain, transformation of A. foetidus and selection of transformed TK- A. foetidus have been studied. By using this system, several transformed A. foetidus which contained HBsAg gene derived bf a promoter H8 cloned from genomic DNA of A. foetidus were isolated. It was demonstrated that HBsAg gene was integrated into the chromosome DNA of A. foetidus by Southern blot after many passages of spores. ELISA showed that HBsAg was positive in the growth medium (p/n = 20). The 22 nm particles which were very similar to the HBsAg particles in human serum were found in the growth medium by immunoelectromicroscope. Western blot also gave the specific bands. All these data showed that HBsAg gene was expressed in A. foetidus and the products were secreted into the growth medium. The selection system using TK gene as marker could generally be used to study the expression of foreign gene in A. foetidus.
authors.affiliation: Institute of Microbiology, Academia Sinica, Beijing.
authors.forename: H D
authors.initials: HD
authors.lastname: Liu
authors.forename: X
authors.initials: X
authors.lastname: Cao
authors.forename: X J
authors.initials: XJ
authors.lastname: Wu
authors.forename: L
authors.initials: L
authors.lastname: Ruan
authors.forename: P Y
authors.initials: PY
authors.lastname: Liang
mesh_terms: D001230:Aspergillus / Q000235:genetics*; D003001:Cloning, Molecular; D004279:DNA, Viral; D015967:Gene Expression Regulation, Viral; D005819:Genetic Markers; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D013937:Thymidine Kinase / Q000235:genetics*
chemical_list: D004279:DNA, Viral; D005819:Genetic Markers; D006514:Hepatitis B Surface Antigens; D013937:Thymidine Kinase