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Rapeseed is one of the most important resource of edible oil and vegetable protein, and also can be used in modern industry. With the improvement of people’s life, we need to improve the yield and quality of rapeseed. So, utilization of heterosis to breed the high yield and high quality rapeseed hybrids has become the main aim for rapeseed breeding.Genic male sterility of rapeseed has been widely applied and it is a efficient way to realize heterosis.The mechanism of genic male sterility in Brassica napus has been studied by some researchers. Wu(2006) established the SSH library in dominant genic male sterility Brassica napus L Rs1046AB. The research revealed that there were 212 ESTs expressed differently in the development of male gametogenesis.And there was a assumption that ,the expression of rad23 gene in the sterility materials is weak, so it can not recognize the damaged DNA,therefore,there are abnormal meiosis behaviors in the early development of pollen mother cells, which eventually led to the formation of sterile pollen.Some researches reveal that, rad23 protein has similar function to ubiquitin,and it can bind to the XPC factor, the protein complex can recognize the damaged DNA. If the rad23 gene was inactive, the sensitivity to UV of the cell maybe enhanced, and the procession of repairing DNA is inefficient, which eventually led to damage of the cell.In this paper, the homozygous DGMS two-type line Rs1046AB and two-type heterozygous RGMS 9012AB were used as materials. Two ESTs associated with the DNA repair: 1-B09 (GeneBank accession number: EE392255), 2-I05 (GeneBank accession number: EE392341) was selected in the experiment. In this article, cloning the full length cDNA of rad23 , and function analysis of it were carried out. Primary results are listed as follows:1、Full-length cDNA of this EST: 1-B09, named Brassica napus DNA repair protein RAD23 mRNA (Bnrad23 gene) was cloned (GeneBank accession number: EU306600) in pollen of Rs1046AB using rapid-amplification of cDNA ends(RACE). Promoter regions of Brassica napus DNA repair gene were cloned. Together with the coding sequence it was called Brassica napus RAD23-like gene, promoter region, 5’ UTR, and complete sequence(GenBank accession number: EU306601); The part cDNA of another EST 2-I05 was cloned(GeneBank accession number: EU306599). Characterization and structure of rad23 protein were partially predicted, too.2、Analysis of the expressing of the 2 ESTs were done in Rs1046AB, 9012AB by RT-PCR,the relationship of DNA repair and male sterility in Brassica napus was partially predicted, too.3、By using chromosome walking technique, promoter regions of Bnrad23 gene were cloned from Rs1046AB. Two TATA boxes, three CAAT boxes, five GAAT boxes, several cis elements which have significance for initiating gene pollen-specific expression, and a series of cis elements relevant to stresses were found in the promoter region. There are no difference between sterility and fertility on the genome level of Bnrad23.4、Analysis of the part cDNA of 2-I05, it maybe contain the whole coding sequence .The 2-I05 and the 1-B09 are possibly the same gene family.
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