Cross G A
Rockefeller University, New York, NY 10021-6399, USA
Bioessays. 1996 Apr;18(4):283-91. doi: 10.1002/bies.950180406.
Among pathogenic micro-organisms that evade the mammalian immune responses. Trypanosoma brucei has developed the most elaborate capacity for antigenic variation. Trypanosomes branched early during eukaryotic evolution. They are characterized by many aberrations, ranging from the unusual compartmentation of metabolic pathways to the heresy of RNA editing. The ubiquitous phenomenon of glycosylphosphatidylinositol-anchoring of eukaryotic plasma membrane proteins and RNA trans-splicing (trypanosome genes contain no introns), which adds an identical leader sequence to all trypanosome mRNAs, were first defined during studies of antigenic variation. Genetic transformation of trypanosomes and the high efficiency of gene targeting provide new opportunities to investigate the regulation of antigenic variation. There is every reason to expect trypanosomes to provide further surprises and insights into the evolution of genetic regulatory mechanisms.
在逃避哺乳动物免疫反应的致病微生物中，布氏锥虫形成了最复杂的抗原变异能力。锥虫在真核生物进化早期就已分支。它们具有许多异常特征，从代谢途径的异常区室化到RNA编辑的反常现象。真核细胞质膜蛋白的糖基磷脂酰肌醇锚定这一普遍现象以及RNA反式剪接（锥虫基因不含内含子），后者会给所有锥虫mRNA添加相同的前导序列，这些都是在对抗原变异的研究中首次确定的。锥虫的遗传转化和高效的基因靶向提供了研究抗原变异调控的新机会。完全有理由期待锥虫会为遗传调控机制的进化带来更多惊喜和见解。
