RNA editing can profoundly affect gene expression by altering the coding capacity of a transcript. RNA editing has been reported in transcripts from such organisms as trypanosomes, higher plants, and mammals. In humans, RNA editing is necessary for proper expression of certain genes in the brain and intestine. This process is responsible for the production of two different apolipoproteins from the same gene; as the abundance of one of these proteins is correlated with coronary artery disease, aberrant RNA editing could potentially have serious health consequences. It is likely that additional examples of RNA editing of human gene transcripts remain to be discovered. We propose to study RNA editing in plant organelles as a model for understanding this fundamental process that can control gene expression. Like mammals, plant organelle editing results in the modification of nucleotides rather than the insertion of nucleotides that occurs in trypanosomes and other organisms. The editing activity in chloroplasts and mitochondria may share features or even be identical. A cryptic higher-level genetic code may be specifying which nucleotides are to be altered by the editing process. Structural requirements for RNA editing will be examined in vivo by introduction of chloroplast and mitochondrial RNAs into transiently and stably transformed chloroplasts obtained by particle bombardment. After information about RNA substrate is available, studies will be carried out to characterize the components of the editing activity. To learn whether there is a mechanism that prevents synthesis of proteins from incompletely edited transcripts, or whether translation of unedited RNAs results in multiple variant proteins, we will isolate two mitochondrial proteins and characterize them thoroughly. To determine whether editing has a role in gene regulation, we will perform experiments to determine whether editing of particular genes is tissue-specific.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM050723-01
Application #
2188736
Study Section
Molecular Cytology Study Section (CTY)
Project Start
1994-05-01
Project End
1998-04-30
Budget Start
1994-05-01
Budget End
1995-04-30
Support Year
1
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Cornell University
Department
Genetics
Type
Schools of Arts and Sciences
DUNS #
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Bentolila, Stephane; Chateigner-Boutin, Anne-Laure; Hanson, Maureen R (2005) Ecotype allelic variation in C-to-U editing extent of a mitochondrial transcript identifies RNA-editing quantitative trait loci in Arabidopsis. Plant Physiol 139:2006-16
Hegeman, Carla E; Hayes, Michael L; Hanson, Maureen R (2005) Substrate and cofactor requirements for RNA editing of chloroplast transcripts in Arabidopsis in vitro. Plant J 42:124-32
Hegeman, Carla E; Halter, Christine P; Owens, Thomas G et al. (2005) Expression of complementary RNA from chloroplast transgenes affects editing efficiency of transgene and endogenous chloroplast transcripts. Nucleic Acids Res 33:1454-64
Chateigner-Boutin, Anne-Laure; Hanson, Maureen R (2003) Developmental co-variation of RNA editing extent of plastid editing sites exhibiting similar cis-elements. Nucleic Acids Res 31:2586-94
Chateigner-Boutin, Anne-Laure; Hanson, Maureen R (2002) Cross-competition in transgenic chloroplasts expressing single editing sites reveals shared cis elements. Mol Cell Biol 22:8448-56
Reed, M L; Peeters, N M; Hanson, M R (2001) A single alteration 20 nt 5' to an editing target inhibits chloroplast RNA editing in vivo. Nucleic Acids Res 29:1507-13
Reed, M L; Wilson, S K; Sutton, C A et al. (2001) High-level expression of a synthetic red-shifted GFP coding region incorporated into transgenic chloroplasts. Plant J 27:257-65
Reed, M L; Lyi, S M; Hanson, M R (2001) Edited transcripts compete with unedited mRNAs for trans-acting editing factors in higher plant chloroplasts. Gene 272:165-71
Reed, M L; Hanson, M R (1997) A heterologous maize rpoB editing site is recognized by transgenic tobacco chloroplasts. Mol Cell Biol 17:6948-52
Lu, B; Hanson, M R (1996) Fully edited and partially edited nad9 transcripts differ in size and both are associated with polysomes in potato mitochondria. Nucleic Acids Res 24:1369-74

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