Using the yeast Saccharomyces cerevisiae and the integrative vector system, we have isolated and characterized an autonomously replicating sequence (ARS) from Aspergillus nidulans. The DNA fragment, designated ANRI, is 5.0 kb in size, and to be maintained in free from the chromosome in S. cerevisiae. The recombinant plasmid YIplac211-ANRI, consists of sequences derived from the 3.79 kb yeast integrative vector YIplac211 and ANR1, showed a 10'-fold enhancement of transformation efficiency over that found for YIplac2l 1, and easily recovered from the transformed yeast. Genetic analysis of transformants showed that YIplac2l 1-ANR1 could be cured over 96% when cultured over 20 generation in complete medium suggesting that this sequence should be mitotically unstable. In Aspergillus nidulans, recombinant plasmid pILJ16-4.5 which carries the 4.5 kb EcoRI fragment of ANRl showed a 170-fold enhancement of transformation efficiency compared to that of integrative vector pILJ16. Recombinant plasmid pILJ16-4.5 is mitotically unstable, being lost from 67% of asexual progeny of transformants. Southern analysis of transformant DNA showed pILJ16-4.5 to be maintained in free form. Sequence analysis had confirmed that the ANR1 fragment originated from mitochondiral DNA of A. nidulans.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)