关键词: 菜薹, 蛋白甲基转移酶, 克隆, 序列分析, 时空表达

Abstract: The full length cDNA and gDNA of BrcuPRMT5 were obtained by using RT-PCR and RACE amplification from flowering Chinese cabbage（Brassica rapa syn. campestris ssp. chinensis var. utilis）‘Youqing 49’and‘Youqing Tiancaitai 80’stem apex. BrcuPRMT5 was 2 117 bp in full length and encoded a predicted protein of 642 amino acids（ORF length 1 929 bp）with a molecular mass of 71.55 kD and an isoelectric point of 5.87. Amino acid sequence analysis showed that it contains one conserved domains of PRMT family of protein arginine N-methyltransferase in higher plants. Phylogenetic tree analysis showed that the flowering Chinese cabbage had the closest evolutionary relationship with Chinese cabbage，rape and broccoli. Subcellular localization analysis indicated that it might be targeted to the mitochondrion without transmembrane region. The corresponding gDNA was 4 151 bp in length which harbored 23 exons and 22 introns. The longest extron was 140 bp in length and the length range of introns was 50–150 bp. BrcuPRMT5 was expressed in the root，stem，leaf and flower by the tissue-specificity expression. The expressive content in different tissues was different：the highest was in flower，the next was in stem，and the lowest level was in root. The semi-quantitative RT-PCR and qPCR analysis revealed that no detectable levels were expressed during the first stage of sampling，then transcripts were detected during the two true-leaf，the four true-leaf，the five true-leaf and the flowering stages. This suggests BrcuPRMT5 may play an important role in flowering Chinese cabbage flower development.

Key words: flowering Chinese cabbage, protein arginine N-methyltransferase, clone, sequence analysis, expression