CBT1 interacts genetically with CBP1 and the mitochondrially encoded cytochrome b gene and is required to stabilize the mature cytochrome b mRNA of Saccharomyces cerevisiae.
Mutation of a CCG sequence in the 5'-untranslated region of the mitochondrially encoded cytochrome b mRNA in Saccharomyces cerevisiae results in destabilization of the message and respiratory deficiency of the mutant strain. This phenotype mimics that of a mutation in the nuclear CBP1 gene. Here it is shown that overexpression of the nuclear CBT1 gene, due to a transposon insertion in the 5'-untranslated region, rescues the respiratory defects resulting from mutating the CCG sequence to ACG. Overexpressing alleles of CBT1 are allelic to soc1, a previously isolated suppressor of cbp1ts-induced temperature sensitivity of respiratory growth. Quantitative primer extension analysis indicated that cbt1 null strains have defects in 5'-end processing of precursor cytochrome b mRNA to the mature form. Cbt1p is also required for stabilizing the mature cytochrome b mRNA after 5' processing.
Ellis
Timothy P
TP
Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA.
Schonauer
Melissa S
MS
Dieckmann
Carol L
CL
D045303:Cytochromes b / Q000235:genetics* / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics; D024101:Mitochondrial Proteins; D017354:Point Mutation; D020871:RNA Stability / Q000235:genetics*; D012331:RNA, Fungal / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000378:metabolism; D016601:RNA-Binding Proteins; D018626:Retroelements / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism
C109121:CBT1 protein, S cerevisiae; D024101:Mitochondrial Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D016601:RNA-Binding Proteins; D018626:Retroelements; D029701:Saccharomyces cerevisiae Proteins; C494475:cbp1 protein, S cerevisiae; D045303:Cytochromes b