摘要
昼夜节律钟基因CCA1在调解水稻和拟南芥的光周期反应中起着重要作用。本研究利用从水稻和拟南芥中分离到的CCA1基因序列作为靶序列BLAST获取Genbank中的信息,通过RT-PCR方法克隆获得了一条2326bp的玉米CCA1基因cDNA序列。BLAST比对发现其与水稻、大麦和拟南芥的序列相似性分别达73.7%、69.4%和39.8%。利用NCBI中的ORF Finder软件分析,发现该序列包含一个2163bp的开放阅读框,编码720个氨基酸残基,蛋白的分子量约为78819.17Da,等电点为6.468。推测其含有3个myb-DNA结合域、7个N-豆蔻酰化位点、1个G-box蛋白结合域以及1个蛋白跨膜结合域。采用实时荧光定量PCR分析发现,随光照时间的变化,该基因在玉米叶片中的表达量呈现出白天不断降低而夜晚逐渐升高的昼夜变化趋势。本研究为进一步研究玉米CCA1基因在调控玉米光周期敏感现象中的功能,阐明玉米光周期敏感机制提供了科学依据。
CCA1 gene plays an important role in circadian clock sensitivity in rice（Oryza sative L.） and Arabidopsis thaliana.In this study,CCA1（2326 bp） was cloned by RT-PCR using homological primers based on the highly conserved region of the multiple alignment of the rice and Arabidopsis.CCA1 from GenBank of NCBI.The similarities of these sequences were up to 73.7%,69.4 and 39.8%,respectively,to corresponding mRNA sequences of rice,barley and Arabidopsis in BLAST/nr of GenBank database.Using ORF Finder software,a 2163 bp open reading frame was found to code 720 amino acids.Analyzing this amino acid sequence by Compute pI/Mw tool revealed that the molecular weight of this protein was about 78819.17 Da,and isoelectric point was about 6.468.The amino acid sequence contained three myb-DNA binding domains,seven N-myristoylation sites,one G-box binding domain and one putative transmembrane spanning region.We established fluorescence quantitative RT-PCR system with maize inbred line B73,and studied the expression of CCA1 in leaf under 16h/8h（light/dark） conditions.Expression analysis showed that the gene expression peaked at dawn（ZT0） then gradually declined from ZT0 to ZT15,bottomed at ZT15,then increased and returned to the initial level at ZT24.Our present study will provide information of maize CCA1 gene for further studying the function in regulating photoperiod sensitivity in maize,and provide scientific basis for clarifying the mechanism of the circadian synchronization in maize.
出处
《山西农业大学学报（自然科学版）》
CAS
2011年第4期332-337,共6页
Journal of Shanxi Agricultural University(Natural Science Edition)
基金
山西农业大学科技创新基金(2011013)
