title: Pet127 governs a 5' -> 3'-exonuclease important in maturation of apocytochrome b mRNA in Saccharomyces cerevisiae.
abstract: The details of mRNA maturation in Saccharomyces mitochondria are not well understood. All seven mRNAs are transcribed as part of multigenic units. The mRNAs are processed at a common 3'-dodecamer sequence, but the 5'-ends have seven different sequences. To investigate whether apocytochrome b (COB) mRNA is processed at the 5'-end from a longer precursor by an endonuclease or an exonuclease, a 64-nucleotide sequence, which is required for the protection of COB mRNA by the Cbp1 protein and is found at the 5'-end of the processed COB mRNA, was duplicated in tandem. The wild-type 64-nucleotide element functioned in either the upstream or downstream position when paired with a mutant element. In the tandem wild-type strain, the 5'-end of the mRNA was at the 5'-end of the upstream unit, demonstrating that the mRNA is processed by an exonuclease. Accumulation of precursor COB RNA in single and double element strains with a deletion of PET127 demonstrated that the encoded protein governs the 5'-exonuclease responsible for processing the precursor to the mature form.
authors: Department of Medical Biology, Medical School, University of Pécs, H-7624 Pécs, Hungary.
authors: Zsuzsanna
authors: Z
authors: Fekete
authors: Timothy P
authors: TP
authors: Ellis
authors: Melissa S
authors: MS
authors: Schonauer
authors: Carol L
authors: CL
authors: Dieckmann
mesh_terms: D001483:Base Sequence; D045303:Cytochromes b / Q000235:genetics*; D017931:DNA Primers; D005092:Exonucleases / Q000378:metabolism*; D024101:Mitochondrial Proteins; D012333:RNA, Messenger / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D015534:Trans-Activators / Q000502:physiology*
chemical_list: D017931:DNA Primers; D024101:Mitochondrial Proteins; C077890:PET127 protein, S cerevisiae; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D045303:Cytochromes b; D005092:Exonucleases