Ie protein have multiple functions , such as conversion of the host cell into a metabolically activate states , activation of viral early genes in the early phase , repression of their own transcription . ie 180 proteins can stimulate transcription from both homologous such as the icp4 of hsv ( herpes simplex virus ) and heterologous viral and cellular promoter such as - globe protein 经分析伪狂犬病病毒立即早期蛋白( immediate - earlyprotein180 , ie180 )的蛋白质结构，发现ie180具有转录激活因子的结构特征，能与类rna聚合酶结合， ie180基因缺失突变体对sv40及cmv启动子调控作用的研究，是考察ie180能否作为转录激活因子应用的关键。
The deletion mutants were proved to be genetically stable , and thus might be promising strains in industrial production of avermectins b . although s . avermitilis produces eight related components of avermectins , only two components , bla and bib , are available for the medical , veterinary and agricultural fields 该缺失突变是在染色体上通过同源双交换完成的，不会发生进一步的重组，因此突变株性状稳定，在工业生产上具有应用价值。阿维菌素的天然发酵产物共有八个组分，其中只有b1组分的杀虫活性最高，被作为杀虫剂在农业和畜牧业中使用。
Shaking flask experiments and hplc analyses showed that the four mutants no longer produced the toxic oligomycin , and only made four components of avermectins b , which were avermectin b1a , b1b , b2a , b2b . the yields of avermectins b in these mutants were separately equal to those in cz8 - 73 . this revealed that olma genes deletion did n ' t affect the biosynthesis of avermectins 将4株经southern杂交验证正确的基因缺失突变株进行摇瓶发酵和hplc检测，发现4个突变株均不再产生寡霉素而仅产阿维菌素b组分，阿维菌素的总产量和b1的产量与出发菌株相当，说明寡霉素pks基因簇的缺失并不影响阿维菌素的生物合成。
Two pta - mutants have been selected by using suicide substrate after the mini - tn5 transposon insertion mutagenesis of klebsiella pneumoniae m5al . when used in microaerobic fermentation , the amount of acetate produced by the mutants reduced to less than 50 % of the parent strain , and the yields improved whereas the 1 , 3 - propanediol titers and productivities decreased 以klebsiellapneumoniaem5al为出发菌株，用mini - tn5随机转座诱变结合自杀性底物筛选的方法得到了两株产乙酸途径pta基因缺失突变株xl - 6和xl - 11 ，应用到微氧法发酵中，突变株的乙酸产量为亲株的50以下，甘油转化率有所提高，但1 ， 3 -丙二醇浓度和生产强度有所下降。
