Skip to main content
NCBI home page
The Plant Cell logoLink to The Plant Cell
. 1993 Nov;5(11):1599–1609. doi: 10.1105/tpc.5.11.1599

opaque2 modifiers act post-transcriptionally and in a polar manner on gamma-zein gene expression in maize endosperm.

E Or 1, S K Boyer 1, B A Larkins 1
PMCID: PMC160389  PMID: 8312742

Abstract

The opaque2 (o2) modifier genes convert the soft endosperm of an o2 mutant to a hard, vitreous phenotype. The primary biochemical change associated with the expression of these genes is a two- to threefold increase in synthesis of the 27-kD gamma-zein storage protein. To investigate the mechanism of modifier gene activity, we examined the level of gamma-zein mRNA and protein synthesis during the early stages of endosperm development in normal, o2, and modified o2 geno-types. Although the o2 mutation was found to reduce expression of the 27-kD gamma-zein genes, the activity of o2 modifier genes dramatically increased the level of both gamma-zein protein and mRNAs as early as 16 days after pollination. At this stage, transcription of gamma-zein genes is reduced by approximately 50% in both o2 and modified o2 genotypes compared to wild type. Thus, it appears that the modifiers regulate gamma-zein synthesis through a post-transcriptional mechanism. Analysis of transcripts from the two nearly identical genes (A and B) encoding the 27-kD gamma-zein protein showed differences in the mRNA ratios in different genotypes. In modified o2 mutants, accumulation of A over B transcript was greatly enhanced during endosperm development. Somatic recombination at this locus was found to reduce the number of B genes in the endosperm, but this could not account for the preferential accumulation of the A transcript. Our results suggest that a product of the o2 modifier genes increases the translation or stability of the A gene mRNA, leading to enhanced synthesis of 27-kD gamma-zein protein.

Full Text

The Full Text of this article is available as a PDF (3.1 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Chandler P. M., Higgins T. J., Randall P. J., Spencer D. Regulation of Legumin Levels in Developing Pea Seeds under Conditions of Sulfur Deficiency: Rates of Legumin Synthesis and Levels of Legumin mRNA. Plant Physiol. 1983 Jan;71(1):47–54. doi: 10.1104/pp.71.1.47. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Das O. P., Levi-Minzi S., Koury M., Benner M., Messing J. A somatic gene rearrangement contributing to genetic diversity in maize. Proc Natl Acad Sci U S A. 1990 Oct;87(20):7809–7813. doi: 10.1073/pnas.87.20.7809. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Das O. P., Poliak E., Ward K., Messing J. A new allele of the duplicated 27kD zein locus of maize generated by homologous recombination. Nucleic Acids Res. 1991 Jun 25;19(12):3325–3330. doi: 10.1093/nar/19.12.3325. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dellapenna D., Lincoln J. E., Fischer R. L., Bennett A. B. Transcriptional Analysis of Polygalacturonase and Other Ripening Associated Genes in Rutgers, rin, nor, and Nr Tomato Fruit. Plant Physiol. 1989 Aug;90(4):1372–1377. doi: 10.1104/pp.90.4.1372. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Halazonetis T. D., Georgopoulos K., Greenberg M. E., Leder P. c-Jun dimerizes with itself and with c-Fos, forming complexes of different DNA binding affinities. Cell. 1988 Dec 2;55(5):917–924. doi: 10.1016/0092-8674(88)90147-x. [DOI] [PubMed] [Google Scholar]
  6. Holowach L. P., Thompson J. F., Madison J. T. Storage Protein Composition of Soybean Cotyledons Grown In Vitro in Media of Various Sulfate Concentrations in the Presence and Absence of Exogenous l-Methionine. Plant Physiol. 1984 Mar;74(3):584–589. doi: 10.1104/pp.74.3.584. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Kodrzycki R., Boston R. S., Larkins B. A. The opaque-2 mutation of maize differentially reduces zein gene transcription. Plant Cell. 1989 Jan;1(1):105–114. doi: 10.1105/tpc.1.1.105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Kuppuswamy M. N., Hoffmann J. W., Kasper C. K., Spitzer S. G., Groce S. L., Bajaj S. P. Single nucleotide primer extension to detect genetic diseases: experimental application to hemophilia B (factor IX) and cystic fibrosis genes. Proc Natl Acad Sci U S A. 1991 Feb 15;88(4):1143–1147. doi: 10.1073/pnas.88.4.1143. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  10. Lending C. R., Larkins B. A. Changes in the zein composition of protein bodies during maize endosperm development. Plant Cell. 1989 Oct;1(10):1011–1023. doi: 10.1105/tpc.1.10.1011. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. MERTZ E. T., BATES L. S., NELSON O. E. MUTANT GENE THAT CHANGES PROTEIN COMPOSITION AND INCREASES LYSINE CONTENT OF MAIZE ENDOSPERM. Science. 1964 Jul 17;145(3629):279–280. doi: 10.1126/science.145.3629.279. [DOI] [PubMed] [Google Scholar]
  12. McCarty D. R., Shaw J. R., Hannah L. C. The cloning, genetic mapping, and expression of the constitutive sucrose synthase locus of maize. Proc Natl Acad Sci U S A. 1986 Dec;83(23):9099–9103. doi: 10.1073/pnas.83.23.9099. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Prat S., Cortadas J., Puigdomènech P., Palau J. Nucleic acid (cDNA) and amino acid sequences of the maize endosperm protein glutelin-2. Nucleic Acids Res. 1985 Mar 11;13(5):1493–1504. doi: 10.1093/nar/13.5.1493. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Pysh L. D., Aukerman M. J., Schmidt R. J. OHP1: a maize basic domain/leucine zipper protein that interacts with opaque2. Plant Cell. 1993 Feb;5(2):227–236. doi: 10.1105/tpc.5.2.227. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Singletary G. W., Doehlert D. C., Wilson C. M., Muhitch M. J., Below F. E. Response of enzymes and storage proteins of maize endosperm to nitrogen supply. Plant Physiol. 1990 Nov;94(3):858–864. doi: 10.1104/pp.94.3.858. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Wallace J. C., Lopes M. A., Paiva E., Larkins B. A. New Methods for Extraction and Quantitation of Zeins Reveal a High Content of gamma-Zein in Modified opaque-2 Maize. Plant Physiol. 1990 Jan;92(1):191–196. doi: 10.1104/pp.92.1.191. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from The Plant Cell are provided here courtesy of Oxford University Press

RESOURCES