Andrews G K, Teng C S
Biochem J. 1979 Aug 15;182(2):257-69. doi: 10.1042/bj1820257.
Assays of transcription in vitro, with Escherichia coli RNA polymerase or wheat-germ RNA polymerase II, were used to characterize chromatin templates isolated from the left Müllerian duct of the chick embryo during normal development, and during development in the presence of diethylstilboestrol. Control Müllerian-duct template capacity with E. coli RNA polymerase decreased from 6.42% on day 10 to 4.34% by day 15 of development. Similar results were found with wheat-germ RNA polymerase II. In the presence of rifampicin and heparin, the prokaryotic enzyme transcribed a number-average RNA chain of 670 nucleotide residues, at an average rate of 110 nucleotide residues/min, from Müllerian-duct chromatin of all developmental stages. From day 10 to day 15 there was a 44% decrease in the number of initiation sites for E. coli RNA polymerase on Müllerian-duct chromatin. A 47% decline was observed when these chromatins were transcribed with excess RNA polymerase II in the presence of rifamycin Af/013. Signs of increasing responsiveness to oestrogen developed between days 10 and 16. Embryos exposed to maximally responsive doses of diethylstilboestrol for 2 days showed increases in Müllerian-duct chromatin template capacity, RNA-chain initiation sites, wet weight, protein and RNA. The changes seen in the oviduct of the 1-week-old chick injected for 2 days with diethylstilboestrol were defined as 100% responses. By comparison, the Müllerian duct, after exposure to diethylstilboestrol from day 10 to day 12, from day 13 to day 15 or from day 16 to day 18, showed a 15%, 39% and 72% template response respectively, and a 42%, 56% and 85% initiation-site change respectively. A similar developmental trend was observed in all parameters. It is concluded that oestrogenic responsiveness in the developing Müllerian duct increases from day 10 to nearly maximal values by day 16 of development, and that this transition is paralleled by a progressive restriction of genomic activity.
利用体外转录实验，采用大肠杆菌RNA聚合酶或小麦胚芽RNA聚合酶II，对正常发育期间以及在己烯雌酚存在下发育的鸡胚左中肾管分离出的染色质模板进行表征。在发育第10天，用大肠杆菌RNA聚合酶时，对照中肾管模板活性为6.42%，到发育第15天时降至4.34%。用小麦胚芽RNA聚合酶II也得到了类似结果。在利福平和平肝素存在的情况下，原核酶从所有发育阶段的中肾管染色质转录出平均长度为670个核苷酸残基的数均RNA链，平均速率为每分钟110个核苷酸残基。从发育第10天到第15天，大肠杆菌RNA聚合酶在中肾管染色质上的起始位点数量减少了44%。当这些染色质在利福霉素Af/013存在下用过量RNA聚合酶II转录时，观察到起始位点数量下降了47%。在发育第10天到第16天之间，对雌激素的反应性增加的迹象逐渐显现。暴露于最大反应剂量己烯雌酚2天的胚胎，其左中肾管染色质模板活性、RNA链起始位点、湿重、蛋白质和RNA均增加。给1周龄雏鸡注射己烯雌酚2天，在其输卵管中观察到的变化被定义为100%反应。相比之下，在发育第10天到第12天、第13天到第15天或第16天到第18天暴露于己烯雌酚的左中肾管，其模板反应分别为15%、39%和72%，起始位点变化分别为42%、56%和85%。所有参数均观察到类似的发育趋势。得出的结论是，发育中的左中肾管对雌激素的反应性从发育第10天开始增加，到发育第16天接近最大值，并且这种转变伴随着基因组活性的逐渐受限。
