Autonomously Replicating Linear Plasmids That Facilitate the Analysis of Replication Origin Function in Candida albicans

Circular plasmids are important tools for molecular manipulation in model fungi such as baker’s yeast, yet, in Candida albicans , an important yeast pathogen of humans, prior studies were not able to generate circular plasmids that were autonomous (duplicated without inserting themselves into the chromosome). Here, we found that linearizing circular plasmids with sequences from telomeres, the chromosome ends, allows the plasmids to duplicate and segregate in C. albicans . We used this system to identify chromosomal sequences that facilitate the initiation of plasmid replication (origins) and to show that an ∼100-bp fragment of a C. albicans origin and an origin sequence from a distantly related yeast can both function as origins in C. albicans . Thus, the requirements for plasmid geometry, but not necessarily for origin sequences, differ between C. albicans and baker’s yeast.