srd1, a Saccharomyces cerevisiae suppressor of the temperature-sensitive pre-rRNA processing defect of rrp1-1

We define a new gene, SRD1, involved in the processing of pre-rRNA to mature rRNA. The SRD1 gene was identified by selecting for second-site suppressors of the previously described rrp1-1 mutation. The rrp1-1 mutation causes temperature-sensitive growth, a conditional defect in processing of 27S pre-rRNA to mature 25S rRNA, and a nonconditional increase in sensitivity to several aminoglycoside antibiotics. All srd1 alleles identified are recessive and apparently specific to the rrp1-1 mutation. Although a mutation of SRD1 suppresses the pre-rRNA processing defect, drug sensitivity and thermolethality of a point mutation of RRP1, it is unable to suppress a rrp1-disruption allele. We suggest that the SRD1 gene product either interacts with or regulates the RRP1 product.