Birse C E, Clutterbuck A J
Department of Genetics, Glasgow University, Scotland, U.K.
Gene. 1991 Feb 1;98(1):69-76. doi: 10.1016/0378-1119(91)90105-k.
Ivory (ivo) mutants of Aspergillus nidulans lack conidiophore pigmentation. We have cloned ivoB which codes for a conidiophore-specific phenol oxidase (AHTase) via the adjacent selectable ureD gene. Gene-library transformants of a ureD4 strain proved defective for the vector, but we recovered both ureD and ivoB from a lambda library of transformant DNA. The ivoB transcription unit was localized to a SalI-XbaI 3-kb fragment and its 5' end was located by hybridization with an oligodeoxyribonucleotide corresponding to the N-terminal polypeptide sequence of AHTase. Expression of the ivoB 1.4-kb mRNA corresponded temporally with AHTase in conidiating cultures, and the levels of both mRNA and AHTase in leaky brlA mutants implied transcriptional control by brlA. A second developmentally regulated locus of unknown function adjacent to ivoB was also transcriptionally dependent on brlA, but was expressed 4 h later.
构巢曲霉的象牙色（ivo）突变体缺乏分生孢子梗色素沉着。我们通过相邻的可选脲酶D基因克隆了编码分生孢子梗特异性酚氧化酶（AHTase）的ivoB。脲酶D4菌株的基因文库转化体被证明对载体有缺陷，但我们从转化体DNA的λ文库中获得了脲酶D和ivoB。ivoB转录单元定位于一个3 kb的SalI-XbaI片段，其5'端通过与对应于AHTase N端多肽序列的寡脱氧核糖核苷酸杂交确定。在产分生孢子的培养物中，ivoB 1.4 kb mRNA的表达在时间上与AHTase相对应，渗漏型brlA突变体中mRNA和AHTase的水平表明受brlA转录调控。与ivoB相邻的另一个功能未知的发育调控位点在转录上也依赖于brlA，但在4小时后表达。
