title: Identification and characterization of promoters specifically and strongly expressed in maize embryos.
abstract: The use of maize seeds as bioreactors has several advantages for the production of recombinant proteins in plant biotechnology, but available embryo-specific and strong promoters are limited. Here, we describe a genome-scale microarray-based approach to identify embryo-specifically and strongly expressed genes and their promoters in maize. We identified 28 embryo-preferred and abundantly expressed genes based on our microarray data. These embryo-preferred genes were further analysed using the UniGene database and by quantitative reverse transcriptase-PCR leading to the identification of seven genes (Zm.2098, Zm.13387, Zm.66589, Zm.85502, Zm.68129, Zm.3896 and Zm.2941) as embryo-specific genes with higher expression levels relative to maize globulin-1. The putative promoters of five embryo-specific genes (Zm.13387, Zm.66589, Zm.85502, Zm.3896 and Zm.2941) were isolated and all exhibited strong promoter activities when transiently expressed in maize embryos of 20 DAP. The embryo specificity and expression levels of the promoters of four genes (Zm.13387, Zm.85502, Zm.3896 and Zm.2941) were further examined in transgenic maize plants, revealing that they are strong promoters in embryos of all four developmental stages tested compared with reference globulin-1 promoter. Moreover, Zm.2941 and Zm.3896 promoters are stringently embryo-specific promoters, while Zm.85502 promoter is basically embryo specific yet wounding inducible in non-seed tissues, and Zm.13387 promoter is developmentally expressed in both embryo and aleurone with wounding-induced activity in non-seed tissues. Our study provides novel embryo-specific and strong promoters that are suitable for production of high-level recombinant proteins in maize embryos.
authors: Faculty of Maize Functional Genomics, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China; National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, China.
authors: Xiaoqing
authors: X
authors: Liu
authors: Jian
authors: J
authors: Tian
authors: Xiaojin
authors: X
authors: Zhou
authors: Rumei
authors: R
authors: Chen
authors: Lei
authors: L
authors: Wang
authors: Chunyi
authors: C
authors: Zhang
authors: Jun
authors: J
authors: Zhao
authors: Yunliu
authors: Y
authors: Fan
mesh_terms: D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017403:In Situ Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D009928:Organ Specificity / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D016372:RNA, Antisense / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics*; D003313:Zea mays / Q000196:embryology* / Q000235:genetics*
chemical_list: D016372:RNA, Antisense; D012333:RNA, Messenger
keywords: embryo-specific and strong promoter; immature embryo transient expression system; microarray analysis; transgenic maize plants