Wickstead Bill, Ersfeld Klaus, Gull Keith
School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, Manchester M13 9PT, UK.
Nucleic Acids Res. 2003 Jul 15;31(14):3993-4000. doi: 10.1093/nar/gkg445.
We have investigated the effect of target copy number on the efficiency of stable transformation of the protozoan parasite Trypanosoma brucei. Using a single strain of the organism, we targeted integrative vectors to several different genomic sequences, occurring at copy numbers ranging from 1 to approximately 30,000 per diploid genome, and undertook a systematic assessment of both transformation and integration efficiencies. Even over this vast copy number range, frequency of gene targeting was the same for all sites. An independence of targeting frequency and target copy number is characteristic of mammalian homologous recombination and is unlike the situation in budding yeast. It is also not seen in the related parasite Leishmania, a distinction that may be the consequence of the different usage of recombination within the mechanisms of pathogenicity in the two species.
我们研究了目标拷贝数对原生动物寄生虫布氏锥虫稳定转化效率的影响。我们使用该生物体的单一菌株,将整合载体靶向到几个不同的基因组序列,这些序列在每个二倍体基因组中的拷贝数范围为1至约30000,并对转化和整合效率进行了系统评估。即使在这个巨大的拷贝数范围内,所有位点的基因靶向频率都是相同的。靶向频率与目标拷贝数无关是哺乳动物同源重组的特征,与出芽酵母的情况不同。在相关寄生虫利什曼原虫中也未观察到这种情况,这种差异可能是由于这两个物种在致病性机制中重组的使用方式不同所致。