Maize Genetics Cooperation Newsletter

maize gene review

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


Review: pending

Pub date: May 2009

Name: rnc1 -- RNAse III domain protein1

Synonyms: RNaseIII, idp1680, si614043c10, PZA00812

Chromosome 3L bin 3.06
Genome Browser,via cDNA EF650835|gi|149980666

Function: chloroplast RNA splicing

image of corn mutant

Summary: Chloroplast RNAse III domain protein: required for the splicing of many chloroplast introns. Null alleles of rnc1 condition albino stunted seedlings. Weak alleles condition pale green seedlings. Both mutant classes are non-photosynthetic and seedling lethal due to the loss of chloroplast ribosomes and the reduced accumulation of all photosynthetic enzyme complexes. RNC1 functions in the context of heterodimeric complexes with WTF1.

Images: mutant leaf color on a seedling leaf color scale

First report: Watkins et al. 2007

Key Alleles:

rnc1-1::Mu1; Mu1 insertion is 54 bp upstream of the start codon; pale green, seedling lethal phenotype.

rnc1-2::Mu1; Mu1 insertion is 11 bp upstream of the start codon; albino (ivory), seedling lethal phenotype.

rnc1-3::Mu3; Mu3 insertion is in the first exon; albino (ivory), seedling lethal phenotype. These seedlings are stunted.

Heteroallelic progeny of complementation crosses between rnc1-1 and rnc1-2 or rnc1-3 have an intermediate pale yellow green phenotype.

Similar crosses between rnc1-2 and rnc1-3 produce ivory seedlings that are not stunted.

Map Location

Based on recombination-based mapping with insertion-deletion probe IDP1680, Fu et al. 2006); and direct hybridization to B73 BAC physical map with overgo probe si14043c10_ov (Gardiner et al. 2004).

Gene Product

RNC1 polypeptide, promotes splicing of chloroplast group IIA and group IIB introns; contains 2 RNase III domains; has no endonuclease activity, binds non-specifically to single and double-stranded RNA (Watkins et al 2007).

Related Loci

wtf1; the WTF1 polypeptide forms a heterodimeric complex with the RNC1 polypeptide (Kroeger et al 2009).


Fu Y, Wen T, Ronin Y, Chen HD, Guo L, Mester D, Yang Y, Lee M, Korol AB, Ashlock D, Schnable P (2006) Genetic dissection of intermated recombinant inbred lines using a new genetic map of maize. Genetics 174(3):1671-1683. PUBMED

Gardiner J, Schroeder S, Schaeffer (Polacco) ML, Sanchez-Villeda H, Fang Z, Morgante M, Landewe T, Fengler K, Useche F, Hanafey M, Tingey SV, Chou H, Wing R, Soderlund CA, Coe E (2004) Anchoring 9,371 maize expressed sequence tagged unigenes to the bacterial artificial chromosome contig map by two-dimensional overgo hybridization. Plant Physiology 134:1317-1326. PUBMED

Kroeger TS, Watkins KP, Friso G, van Wijk KJ, Barkan A (2009) A plant-specific RNA-binding domain revealed through analysis of chloroplast group II intron splicing. Proc Natl Acad Sci U S A 106:4537-4542. PUBMED

Watkins KP, Kroeger TS, Cooke AM, Williams-Carrier RE, Friso G, Belcher SE, van Wijk KJ, Barkan A (2007) A ribonuclease III domain protein functions in group II intron splicing in maize chloroplasts. Plant Cell 19:2606-23. PUBMED

Links: MGDB rnc1 NCBI: rnc1 UniProt: A6YSL1