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

为了阐明植物生长调节剂对植物分化的调控机制，对胡萝卜悬浮培养细胞中的转录调控因子进行了研究。本研究从胡萝卜悬浮培养细胞花青素合成诱导的消减文库中克隆了动物细胞中被称为原癌基因的转录调控因子MYB相关基因。分离了5个MYB相关基因(DCmyb8、DCmyb10、DCmyb12、DCmyb14和DCmyb35)，并测定了它们的核苷酸序列。DCmyb10和DCmyb12具有很高的相似性(核苷酸序列相似性98%)，但其核苷酸序列相似性低于55%，氨基酸序列相似性低于70%。以每个MYB相关基因的特定核苷酸序列为探针，分析了这些基因在胡萝卜培养细胞去分化生长、低分化状态下诱导花青素合成或胚胎发生以及胡萝卜愈伤组织培养的花青素合成突变细胞系和胚性细胞系中的表达模式。DCmyb8和DCmyb10(12)均在分化状态下的花青素合成细胞中表达。在一个花青素合成突变细胞系中观察到DCmyb10的表达，而DCmyb8没有表达。DCmyb14和DCmyb35在胚胎发育过程中的细胞中均有表达，尤其是在球状细胞中表达更明显。这些结果表明，MYB基因在不同分化状态下的细胞中以不同的方式表达，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.