The long-term goal of the proposed research is to better understand host cell-organelle interactions. Specifically this grant addresses the role of nuclear-coded proteins in the expression of the cytochrome b, COB, mitochondrial mRNA in Saccharomyces cerevisiae. cbp1p interacts with the distal portion of the untranslated leader of COB mRNA to promote stability of the message, while cbs1p and Cbs2p interact with the proximal portion of the leader to promote translation.
The Specific Aims of this proposal are: 1) To identify proteins that interact with Cbp1p and COB mRNA to promote stability of the mRNA via reversion analyses, a dihybrid screen and biochemical analyses. 2) To determine the sequence element and/or secondary structures that are important in the region of COB mRNA that interacts with cbplp via site-directed mutagenesis and a physical analysis of the in vivo structure of the RNA. 3) To determine the directionality of decay of COB mRNA in vivo to begin to elucidate the mechanism of turnover. An RNA structure that is resistant to exonucleolytic decay will be inserted at intervals in the mRNA to investigate whether the message is primarily degraded by 5' to 3' or 3' to 5' exonucleases or 5'-dependent endonucleases. 4) To determine the sequence element and/or secondary structures that are important in the regions of COB mRNA that are required for translation via linker-scanning mutagenesis and physical analysis of the in vivo structure of the RNA. These studies will expand the understanding of RNA-protein interactions specifically and in general will contribute to furthering the knowledge of organelle function in eukaryotic cells. Defects in mitochondrial function have been implicated in muscle wasting diseases, aging and lethal genetically inherited disorders. Thus, it is important that the details of nuclear control of mitochondrial function be elucidated.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM034893-12
Application #
2684796
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1985-04-01
Project End
1999-03-31
Budget Start
1998-04-01
Budget End
1999-03-31
Support Year
12
Fiscal Year
1998
Total Cost
Indirect Cost
Name
University of Arizona
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Hiltunen, J Kalervo; Autio, Kaija J; Schonauer, Melissa S et al. (2010) Mitochondrial fatty acid synthesis and respiration. Biochim Biophys Acta 1797:1195-202
Hiltunen, J Kalervo; Schonauer, Melissa S; Autio, Kaija J et al. (2009) Mitochondrial fatty acid synthesis type II: more than just fatty acids. J Biol Chem 284:9011-5
Schonauer, Melissa S; Kastaniotis, Alexander J; Kursu, V A Samuli et al. (2009) Lipoic acid synthesis and attachment in yeast mitochondria. J Biol Chem 284:23234-42
Fekete, Zsuzsanna; Ellis, Timothy P; Schonauer, Melissa S et al. (2008) Pet127 governs a 5'->3'-exonuclease important in maturation of apocytochrome b mRNA in Saccharomyces cerevisiae. J Biol Chem 283:3767-72
Schonauer, Melissa S; Kastaniotis, Alexander J; Hiltunen, J Kalervo et al. (2008) Intersection of RNA processing and the type II fatty acid synthesis pathway in yeast mitochondria. Mol Cell Biol 28:6646-57
Ellis, Timothy P; Schonauer, Melissa S; Dieckmann, Carol L (2005) 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. Genetics 171:949-57
Ellis, Timothy P; Helfenbein, Kevin G; Tzagoloff, Alexander et al. (2004) Aep3p stabilizes the mitochondrial bicistronic mRNA encoding subunits 6 and 8 of the H+-translocating ATP synthase of Saccharomyces cerevisiae. J Biol Chem 279:15728-33
Krause, Kirsten; Dieckmann, Carol L (2004) Analysis of transcription asymmetries along the tRNAE-COB operon: evidence for transcription attenuation and rapid RNA degradation between coding sequences. Nucleic Acids Res 32:6276-83
Krause, Kirsten; Lopes de Souza, Renata; Roberts, Douglas G W et al. (2004) The mitochondrial message-specific mRNA protectors Cbp1 and Pet309 are associated in a high-molecular weight complex. Mol Biol Cell 15:2674-83
Islas-Osuna, Maria A; Ellis, Timothy P; Mittelmeier, Telsa M et al. (2003) Suppressor mutations define two regions in the Cbp1 protein important for mitochondrial cytochrome b mRNA stability in Saccharomyces cerevisiae. Curr Genet 43:327-36

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