Maize Genetics Cooperation Newsletter

maize gene review

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


Review: pending

Pub date: May 2009

Name: wtf1 what's this factor?1

Chromosome 8S bin 8.03
Genome Browser via cDNA EU968423 |gi| 195642145. Note, this BAC region was first assigned to chromosome 1.

Function: chloroplast RNA splicing

image of corn mutant

Summary: wtf1 encodes an RNA binding protein required for chloroplast RNA splicing; WTF1 functions in the context of heterodimeric complexes with RNC1. It harbors an RNA binding domain formerly called DUF860, but renamed the PORR (plant organelle RNA recognition) domain. Null alleles of wtf1 condition albino seedlings. Weak mutant 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.

Image: mutant leaf color depicted on a seedling color scale

First report: Kroeger et al. 2009.

Key Alleles

wtf1-1::MuDR; MuDR insertion is 34 bp upstream of the start codon. Pale green, seedling lethal phenotype.

wtf1-3::Mu1;  Mu1 insertion is 505 bp downstream of the start codon in the exon. Albino (ivory), seedling lethal phenotype.

wtf1-4: :Mu1; Mu1 insertion is 560 bp downstream of the start codon in the exon. Albino (ivory), seedling lethal phenotype.

Heteroallelic progeny of complementation crosses between wtf1-1 and wtf1-3 or wtf1-4 have an intermediate, pale yellow green. phenotype. Heteroallelic wtf1-3/wtf1-4 individuals are ivory and seedling lethal.

Map Location

Mapped by alignment to the B73 Reference Genome Sequence Version 1. Note, this region, on chromosome 8 was originally assigned to chromosome 1.

Gene Product

WTF1 is localized to chloroplast stroma; has a novel RNA binding motif, PORR (plant organelle RNA recognition); and participates in group II intron splicing.

Related Locus

rnc1, encodes a polypeptide that forms an active heterodimer with WTF1.


The wtf1 sequence was originally derived from BAC AC191930 and confirmed by PCR amplification of B73 genomic DNA.


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. 106:4537-42. PUBMED

Links: MGDB: wtf1 NCBI:FJ264201 UniProt: B6TTV8