Puig S, Pérez-Ortín J E, Matallana E
Departamento de Bioquímica y Biología Molecular, Universitat de València, Valencia, Spain.
Curr Microbiol. 1999 Dec;39(6):369-0373. doi: 10.1007/s002849900474.
The exceptionally close packing of many yeast genes and other chromosomal elements raises the question of how those elements are functionally insulated. All published work shows that natural insulators are very effective, but transcriptional interference (TI) occurs if they are mutated or if their natural context is altered. Mechanisms to avoid TI are poorly understood, but are thought to involve an interplay of cis sequences and trans factors in a chromatin context. We have studied the case of two convergent closely packed ORFs (56 bp of separation) in chromosome IX of Saccharomyces cerevisiae. mRNAs from POT1 and YIL161w overlap by up to 115 nt. Convergent transcription causes a small but noticeable negative effect on the level of POT1 mRNA and nucleosome displacement in the intergenic region. This suggests for the first time that some TI could occur in convergently transcribed yeast genes, even in a natural chromosomal context.
许多酵母基因和其他染色体元件的异常紧密排列引发了这些元件如何在功能上实现隔离的问题。所有已发表的研究都表明，天然绝缘子非常有效，但如果它们发生突变或其天然环境发生改变，就会出现转录干扰（TI）。避免TI的机制目前了解甚少，但人们认为这涉及染色质环境中顺式序列和反式因子的相互作用。我们研究了酿酒酵母IX号染色体上两个紧密相邻的反向开放阅读框（间隔56个碱基对）的情况。POT1和YIL161w的mRNA重叠长度可达115个核苷酸。反向转录对POT1 mRNA水平和基因间区域的核小体位移产生了微小但明显的负面影响。这首次表明，即使在天然染色体环境中，一些TI也可能在反向转录的酵母基因中发生。
