uvsFRFC1, the large subunit of replication factor C in Aspergillus nidulans, is essential for DNA replication, functions in UV repair and is upregulated in response to MMS-induced DNA damage

uvsF201 was the first highly UV-sensitive repair-defective mutation isolated in Aspergillus nidulans. It showed epistasis only with postreplication repair mutations, but caused lethal interactions with many other repair-defective strains. Unexpectedly, closest homology of uvsF was found to the large subunit of human DNA replication factor RFC that is essential for DNA replication. Sequencing of the uvsF201 region identified changes at two close base pairs and the corresponding amino acids in the 5′-region of uvsFRFC1. This viable mutant represents a novel and possibly important type. Additional sequencing of the uvsF region confirmed a mitochondrial ribosomal protein gene, mrpAL16, closely adjacent, head-to-head with a 0.2 kb joint promoter region. MMS-induced transcription of both the genes, but especially uvsFRFC1, providing evidence for a function in DNA damage response.