Maize Genetics Cooperation Newsletter

maize gene review

Author: Alice Barkan, University of Oregon, Eugene, OR. USA 97403

DOI/

Review: pending

Pub date: May 2009

Name: ppr5-pentricopeptide repeat5

Chromosome 4L bin 4.08
Genome Browser via cDNA EU037901 | GI:154520280

Function: chloroplast trnG maturation

image of corn mutant

Summary: Encodes a chloroplast PPR protein that stabilizes unspliced trnG precursor RNA by masking an endonuclease-sensitive site in the intron. PPR5 may also promote trnG group II intron splicing. The null allele of ppr5 (ppr5-1) conditions albino seedlings; a weak allele (ppr5-2) conditions pale green seedlings. Both are non-photosynthetic and seedling lethal due to the failure to accumulate mature trnG. The absence of this tRNA blocks the biogenesis of the plastid translation machinery, which in turn leads to the loss of all plastid-encoded proteins.

Images: mutant leaf color on a seedling leaf color scale

First defining reports: Beick et al. 2008; Williams-Carrier et al. 2008.

Key Alleles

ppr5-1::Mu1. Mu1 insertion is in the first exon. Ivory, seedling lethal phenotype. Mutants are smaller than wild type siblings (Beick et al. 2008).

ppr5-2::Mu1. Mu1 insertion in the 5' UTR. Slightly pale green, seedling lethal phenotype (Beick et al. 2008).

ppr5-1::Mu1/ppr5-2::Mu1 individuals are intermediate in phenotype: very pale yellow green at the base with darker green leaf tips (Beick et al. 2008).

Gene Product

PPR5 - required for chloroplast trnG maturation; specifically binds to a ~45-51 nt region of trnG precursor group II intron, covering two group II functional intron motifs (Williams-Carrier et al 2008).

Other

Null alleles of Arabidopsis PPR5 (At4g39620) are embryo lethal (Cushing et al. 2005).

References

Beick S, Schmitz-Linneweber C, Williams-Carrier R, Jensen B, Barkan A (2008) The pentatricopeptide repeat protein PPR5 stabilizes a specific tRNA precursor in maize chloroplasts. Molecular and Cellular Biology 28:5337-5347. PUBMED

Cushing DA, Forsthoefel NR, Gestaut DR, Vernon DM (2005) Arabidopsis emb175 and other ppr knockout mutants reveal essential roles for pentatricopeptide repeat (PPR) proteins in plant embryogenesis. Planta 221:424-436. PUBMED

Williams-Carrier R, Kroeger T, Barkan A (2008) Sequence-specific binding of a chloroplast pentatricopeptide repeat protein to its native group II intron ligand. RNA 14:1930-1941. PUBMED

Links: MGDB: ppr5 NCBI: ppr5 UniProt: A6YSL1