title: Direct and indirect gene replacements in Aspergillus nidulans.
abstract: We performed three sets of experiments to determine whether cloned DNA fragments can be substituted for homologous regions of the Aspergillus nidulans genome by DNA-mediated transformation. A linear DNA fragment containing a heteromorphic trpC+ allele was used to transform a trpC- strain to trpC+. Blot analysis of DNA from the transformants showed that the heteromorphic allele had replaced the trpC- allele in a minority of the strains. An A. nidulans trpC+ gene was inserted into the argB+ gene, and a linear DNA fragment containing the resultant null argB allele was used to transform a trpC- argB+ strain to trpC+. Approximately 30% of the transformants were simultaneously argB-. The null argB allele had replaced the wild-type allele in a majority of these strains. The A. nidulans SpoC1 C1-C gene was modified by removal of an internal restriction fragment and introduced into a trpC- strain by transformation with a circular plasmid. A transformant containing a tandem duplication of the C1-C region separated by plasmid DNA was self-fertilized, and trpC- progeny were selected. All of these had lost the introduced plasmid DNA sequences, whereas about half had retained the modified C1-C gene and lost the wild-type copy. Thus, it is possible with A. nidulans to replace chromosomal DNA sequences with DNA fragments that have been cloned and modified in vitro by using either one- or two-step procedures similar to those developed for Saccharomyces cerevisiae.
authors.forename: B L
authors.initials: BL
authors.lastname: Miller
authors.forename: K Y
authors.initials: KY
authors.lastname: Miller
authors.forename: W E
authors.initials: WE
authors.lastname: Timberlake
mesh_terms: D001233:Aspergillus nidulans / Q000235:genetics*; D002454:Cell Differentiation; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D004271:DNA, Fungal / Q000235:genetics; D005786:Gene Expression Regulation; D005800:Genes, Fungal; D010957:Plasmids; D014170:Transformation, Genetic
chemical_list: D004271:DNA, Fungal; D004262:DNA Restriction Enzymes