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Journal of Biomedicine and Biotechnology
Volume 2012 (2012), Article ID 752391, 8 pages
http://dx.doi.org/10.1155/2012/752391
Research Article

Expression Pattern of the Alpha-Kafirin Promoter Coupled with a Signal Peptide from Sorghum bicolor L. Moench

1School of Pharmacy, The University of Queensland, Brisbane, QLD 4072, Australia
2School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
3Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD 4072, Australia

Received 1 August 2011; Revised 9 October 2011; Accepted 11 October 2011

Academic Editor: J. Birchler

Copyright © 2012 Norazlina Ahmad et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Regulatory sequences with endosperm specificity are essential for foreign gene expression in the desired tissue for both grain quality improvement and molecular pharming. In this study, promoters of seed storage α-kafirin genes coupled with signal sequence (ss) were isolated from Sorghum bicolor L. Moench genomic DNA by PCR. The α-kafirin promoter (α-kaf) contains endosperm specificity-determining motifs, prolamin-box, the O2-box 1, CATC, and TATA boxes required for α-kafirin gene expression in sorghum seeds. The constructs pMB-Ubi-gfp and pMB-kaf-gfp were microprojectile bombarded into various sorghum and sweet corn explants. GFP expression was detected on all explants using the Ubi promoter but only in seeds for the α-kaf promoter. This shows that the α-kaf promoter isolated was functional and demonstrated seed-specific GFP expression. The constructs pMB-Ubi-ss-gfp and pMB-kaf-ss-gfp were also bombarded into the same explants. Detection of GFP expression showed that the signal peptide (SP)::GFP fusion can assemble and fold properly, preserving the fluorescent properties of GFP.