Classification and characterization of the rice α-amylase multigene family
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- Huang, N., Sutliff, T.D., Litts, J.C. et al. Plant Mol Biol (1990) 14: 655. doi:10.1007/BF00016499
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To establish the size and organization of the rice α-amylase multigene family, we have isolated 30 α-amylase clones from three independent genomic libraries. Partial characterization of these clones indicates that they fall into 5 hybridization groups containing a total of 10 genes. Two clones belonging to the Group 3 hybridization class have more than one gene per cloned fragment. The nucleotide sequence of one clone from Group 1, λOSg2, was determined and compared to other known cereal α-amylase sequences revealing that λOSg2 is the genomic analog of the rice cDNA clone, pOS103. The rice α-amylase genes in Group 1 are analogous to the α-Amy1 genes in barley and wheat. λOSg2 contains sequence motifs common to most actively transcribed genes in plants. Two consensus sequences, TAACAGAA and TATCCAT, were found in the 5′ flanking regions of α-amylase genes of rice, barley and wheat. The former sequence may be specific to α-amylase gene while the latter sequence may be related to a ‘CATC’ box found in many plant genes. Another sequence called the pyrimidine box (TCCTTTTTC) was found in the α-amylase genes as well as other genes regulated by gibberellic acid (GA). Comparisons based on amino acid sequence alignment revealed that the multigene families in rice, barley and wheat shared a common ancestor which contained three introns. Some of the descendants of the progenitor α-amylase gene appear to have lost the middle intron while others maintain all three introns.