tailieunhanh - Báo cáo khoa học: A new rice zinc-finger protein binds to the O2S box of the a-amylase gene promoter

A putative transcription factor, named RAMY, that binds to the 20-bp O2S sequences of the regulatory region of the Amy2genepromoter has been identifiedusing the yeast one-hybrid system from a rice library. The full lengthRAMY cDNA clone encodes a 218-amino acid protein and is homologous to the late embryogenesis-abundant protein (LEA5). In vitromutagenesis and electrophoretic mobility shift assays confirmed that RAMY can bind with O2S spe-cifically throughanunusual zincfingerwithaCXCX4CX2H consensus sequence. . | Eur. J. Biochem. 271 2949-2955 2004 FEBS 2004 doi A new rice zinc-finger protein binds to the O2S box of the a-amylase gene promoter Rihe Peng1 Quanhong Yao1 Aisheng Xiong1 Huiqin Fan1 Xian Li1 Youliang Peng2 Zong-Ming Cheng3 and Yi Li4 Shanghai Key Laboratory of Agricultural Genetic and Breeding Agro-Biotechnology Research Center Shanghai Academy of Agricultural Sciences China 2 Department of Plant Pathology Chinese Agricultural University Beijing China 3 Department of Plant Sciences University of Tennessee Knoxville USA 4Department of Plant Science University of Connecticut Storrs USA A putative transcription factor named RAMY that binds to the 20-bp O2S sequences of the regulatory region of the Amy2 gene promoter has been identified using the yeast one-hybrid system from a rice library. The full length RAMY cDNA clone encodes a 218-amino acid protein and is homologous to the late embryogenesis-abundant protein LEA5 . In vitro mutagenesis and electrophoretic mobility shift assays confirmed that RAMY can bind with O2S specifically through an unusual zinc finger with a CXCX4CX2H consensus sequence. Low levels of RAMY mRNAs were detected in rice leaves and roots by Northern blot hybrid ization. The plant hormone gibberellin GA induces expression of both RAMY and Amy2 genes as performed by Northern blot hybridization but the increase in RAMY mRNA level occurs prior to that of the Amy2 mRNA level in the GA-treated aleurone tissues. These data suggest that RAMY may act as a trans-acting protein and is probably involved in the GA-induced expression of the rice a-amylase gene. Keywords rice zinc-induced protein O2S box yeast one-hybrid system. Cereal a-amylase genes have been one of the primary systems for exploring the molecular mechanisms involved in hormone-regulated gene expression in plants. During germination of cereal grains the embryo releases GA to the aleurone layer where it induces the transcription of a-amylase genes 1 . .