Transcription regulatory factors in carrot suspension cultured cells regulated by auxin.

为了阐明植物生长调节物质对植物分化的调控机制，以胡萝卜悬浮培养细胞为材料，研究了转录调控因子。本研究从胡萝卜悬浮培养细胞诱导花青苷合成的消减cDNA文库中分离了myb相关基因，该基因是动物细胞中的一种转录调控因子，被称为原癌基因。克隆了5个myb相关基因（DCmyb 8、DCmyb 10、DCmyb 12、DCmyb 14和DCmyb 35），并测定了它们的核苷酸序列。DCmyb 10和DCmyb 12的核苷酸序列高度相似（98%的相似性），但其他人的核苷酸序列相似性低于55%，翻译的氨基酸序列相似性低于70%。使用各myb相关基因的特定核苷酸序列作为探针，分析了这些基因在去分化生长的胡萝卜培养细胞中、在诱导花色素苷合成或胚胎发生的分化状态下、以及在胡萝卜愈伤组织培养物的花色素苷合成突变细胞系或胚胎发生细胞系中的表达模式。DCmyb 8和DCmyb 10（12）均在分化状态下的花青素合成细胞中表达。DCmyb 14和DCmyb 35在胚状体细胞中均有表达，其中DCmyb 35在球形胚状体细胞中表达最强。这些结果表明，所分离的myb基因在不同分化状态的细胞中以不同的方式表达，并且单个基因可能调控参与不同分化过程的基因的表达。

In order to elucidate the regulatory mechanisms of plant differentiation by plant growth regulators, transcription regulatory factors were investigated in carrot suspension cultured cells. In this research, myb related genes, one of transcription regulatory factors known as proto-oncogene in animal cells, were isolated from subtracted cDNA libraries of carrot suspension cultured cells induced for anthocyanin synthesis. Five clones of myb related genes (DCmyb8, DCmyb10, DCmyb12, DCmyb14 and DCmyb35) were isolated and their nucleotide sequences were determined. DCmyb10 and DCmyb12 were highly similar (98% similarity in nucleotide sequences), but the others had less identity than 55% in nucleotide sequences or 70% in translated amino acid sequences. Using specific nucleotide sequences of each myb related genes as probes, expression patterns of these genes were analyzed in carrot cultured cells under dedifferentiated growth, under differentiated states inducing for anthocyanin synthesis or embryogenesis, and in an anthocyanin-synthesizing mutant cell line or an embryogenic cell line of carrot callus cultures. Both DCmyb8 and DCmyb10 (12) expressed in anthocyanin-synthesizing cells under differentiated states. The expression of DCmyb10 was observed in a mutant cell line synthesizing anthocyanin, but that of DCmyb8 was not in it. DCmyb14 and DCmyb35 expressed in the cells under embryogenesis, especially DCmyb35 did in the cells of globular stage. The results obtained here suggested that myb genes isolated here expressed in cells under different differentiation states in different manners, and that the individual genes might regulate the expression of genes involved in different differentiation process.