2006 journal article

The maize Mucronate mutation is a deletion in the 16-kDa gamma-zein gene that induces the unfolded protein response

PLANT JOURNAL, 48(3), 440–451.

By: C. Kim*, B. Gibbon*, J. Gillikin n, B. Larkins*, R. Boston n & R. Jung*

author keywords: unfolded protein response (UPR); endosperm; protein body; opaque mutant
MeSH headings : Alleles; Amino Acid Sequence; Base Sequence; DNA Primers; Electrophoresis, Gel, Two-Dimensional; Frameshift Mutation; Gene Deletion; Molecular Sequence Data; Polymerase Chain Reaction; Sequence Homology, Amino Acid; Zea mays / genetics; Zein / chemistry; Zein / genetics
TL;DR: Results indicate that the Mc phenotype results from a frame-shift mutation in the gene encoding the 16-kDa gamma-zein protein, leading to the unfolded protein response in developing endosperm. (via Semantic Scholar)
UN Sustainable Development Goal Categories
2. Zero Hunger (Web of Science)
Source: Web Of Science
Added: August 6, 2018

Summary Mucronate (Mc) was identified as a dominant maize (Zea mays L.) opaque kernel mutation that alters zein storage protein synthesis. Zein protein bodies in Mc endosperm are misshapen and are associated with increased levels of ER Lumenal Binding Protein (BiP). Using GeneCallingTM to profile endosperm RNA transcripts, we identified an aberrant RNA in Mc that encodes the 16‐kDa γ‐zein protein. The transcript contains a 38‐bp deletion (nucleotides 406–444 after the initiation codon) that creates a frame‐shift mutation and an abnormal sequence for the last 63 amino acids. Genetic mapping revealed the Mc mutation is linked with the locus encoding the 16‐kDa γ‐zein, and two‐dimensional gel electrophoresis confirmed the 16‐kDa γ‐zein protein is altered in Mc. The mutant protein exhibited changes in solubility properties and co‐immunoprecipitated with the molecular chaperone, BiP. Transgenic maize plants expressing the Mc 16‐kDa γ‐zein manifested an opaque kernel phenotype with enhanced levels of BiP in the endosperm, similar to the Mc mutant. Unlike the wild‐type protein, the Mc 16‐kDa γ‐zein interacted only weakly with the 22‐kDa α‐zein when expressed in the yeast two‐hybrid system. These results indicate that the Mc phenotype results from a frame‐shift mutation in the gene encoding the 16‐kDa γ‐zein protein, leading to the unfolded protein response in developing endosperm.