Multigene Family of Maize Storage Proteins

One gene family in plants that is of environmental and economic importance is seed storage protein genes. They encode proteins that are major biological nitrogen storage and renewable source of essential amino acids for the human and animal diet. In maize the major component is prolamins, also called zeins. Based on sequence clustering and homology relationships, they can be divided into four groups: alpha, beta, gamma, and delta. The youngest group, the alpha zeins, also referred to as zein-1 or z1, are extracted without a reducing agent and arose in the taxonomic subfamily of the Panicoideae some 25 million years ago (mya) and are therefore present in maize, sorghum, and sugarcane. In contrast to sorghum, maize underwent allotetraploidization and has more zein loci than sorghum. There are a total of 11 loci in maize and only 5 in sorghum, but all in syntenic positions. In addition to multiple loci, alpha prolamin genes underwent tandem duplications, again more extensively in maize than in sorghum. Interestingly, alpha zeins differ in the degree of tandem amplification between different inbred lines of maize.This work was supported by DOE (DE–FG05–95ER20194) and NSF (#9975618).

Alpha Zein Clones

Recent Publications on zein related studies:

Xu, J. and Messing, J. (2008). Organization of the prolamin gene family provides insight into the evolution of the maize genome and gene duplications in grass species. Proc. Natl. Acad. Sci. USA 105, 14330-14335.

Xu, J. and Messing, J. (2008). Diverged copies of the seed regulatory Opaque-2 gene by a segmental duplication in the progenitor genome of rice, sorghum, and maize. Mol. Plant 1, 760-769.

Holding, D.R., Hunter, B.G., Chung, T., Gibbon, B.C., Ford, C.F., Bharti, A.K., Messing, J., Hamaker, B.R., and Larkins BA. (2008).
Genetic analysis of opaque2 modifier loci in quality protein maize. Theor Appl Genet. 117, 157-170.

Xu, J. and Messing, J. (2006). Maize haplotype with a helitron-amplified cytidine deaminase gene copy. BMC Genetics 7, e52.

Lai, J., Li, Y., Messing, J., and Dooner, H. (2005). Gene movement by Helitrons contributes to the haplotype variability of maize. Proc. Natl. Acad. Sci. USA. 102, 968-973.

Song, R., Segal, G. and Messing, J. (2004). Expression of the sorghum ten-member kafirin gene cluster in maize endosperm. Nucl. Acids Res. 32, e189.

Segal, G., Song, R., and Messing, J. (2003). A New Opaque Variant of Maize by a Single Dominant RNAi-Inducing Transgene. Genetics 165, 387-397.

Song R and Messing J (2003). Gene expression of a gene family in maize based on noncollinear haplotypes. Proc Natl Acad Sci USA 100, 9055-9060.