Structural organization and differential expression of rice α-amylase genes

Abstract

Rice alpha-amylases are encoded by a multigene family that has previously been classified into 5 hybridization groups. DNA sequence and Southern blot analysis identified three genes (RAmy1A, RAmy1B and RAmy1C) in Group 1 with DNA sequence identity of at least 90%. Hybridization Group 2 is represented by only one gene, RAmy3D, which is identical to a previously characterized cDNA, pOS137. RAmy3D is physically linked to the sole representative of Group 5, RAmy3E. The identity between these two genes is 81.4% in the coding region but less than 50% in the 5' and 3' flanking regions. Northern blot analysis and RNA-PCR were used to detect the expression of alpha-amylase genes in various tissues. Alpha-amylase mRNA was abundant in germinating seeds and callus. Some genes were also expressed at much lower levels in roots, young leaves and immature seeds. RAmy1A and RAmy3E were expressed in all tissues while RAmy3D was expressed in all tissues except the immature seeds. RAmy1B was weakly expressed only in callus. RAmy1A transcript was most abundant in the germinating seeds, while RAmy3D and RAmy3E transcripts were most abundant in callus and immature seeds, respectively.

A Rice WRKY Gene Encodes a Transcriptional Repressor of the Gibberellin Signaling Pathway in Aleurone Cells

“…the a-amylase promoters of barley, wheat, and rice (Huang et al, 1990a(Huang et al, , 1990bO'Neill et al, 1990;Itoh et al, 1995). Indeed, the wheat protease promoter has been shown to be responsible to GA in barley aleurone cells (Mena et al, 2002;Isabel-LaMoneda et al, 2003), and rice effecter genes are functional in barley aleurone cells (Gubler et al, 1997;Lu et al, 2002).…”

Metabolite Signals Regulate Gene Expression and Source/Sink Relations in Cereal Seedlings

“…Relative levels of mRNA for each gene relative to the other genes expressed in that tissue as estimated from northern blot hybridization or RNA-PCR experiments (Huang et al, 1990a;Karrer et al, 1991). Comparison of gene expression from one tissue to another must factor in the total amylase mRNA levels at the top of each column.…”

“…In the DNA sequences for the rice a-amylase genes AmylA and AmyZB, GARE boxes are located approximately 200 bases to the 5' side of the ATG translation start codon (Huang et al, 1990a). Nuclear proteins that bind to the GARE box and other a-amylase promoter cis elements have been identified (Sutliff et al, 1993), including one DNA-binding protein whose production is induced by GA (Goldman et al, 1994).…”

“…GA-insensitive production of a-amylase was also detected in the scutellum tissue of sorghum (ALsien and Palmer, 1983) and barley (MacGregor and Marchylo, 1986). Finally, no GARE boxes were found in the DNA s2quences from the promoters of the Amy3D and Amy3E genej (Huang et al, 1990a). Thus, GA may only accelerate a-amylase gene expression, whereas another regulatory mechanism is required to initiate a-amylase gene expression in the aleurone (Fincher, 1989).…”

Expression Pattern of Arabidopsis Thaliana Pollen- and Embryo-Specific Promoter in Transgenic Tobacco Plants

“…The (CA)n motif was also found in the E8 promoter of tomato ). Finally, the pyrimidine box (CCTTT), AMY1 box (TAACARA) and GAREAT sequence (TAACAAR), motifs occurring in the investigated fragment, are closely related to gibberellin-response elements (Huang et al, 1990;Chavez-Barcenas et al, 2000). Promoters of the above-mentioned motifs are important for temporally and spatially regulated (trans)genes, but other unknown repressors and activators probably determine the resulting expression profile in specific plant tissues (Zhou et al, 2010).…”