脊椎动物转录因子的循环演变
Rachel L Cosby1, Julius Judd1, Ruiling Zhang1
1Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA.
概括
DNA转位子通过异构混合提供新的蛋白质编码序列来推动基因进化. 这一过程多次产生了融合蛋白质,包括像KRAB-转移酶这样的调节蛋白质,形成四足动物基因组.
科学领域:
- 进化遗传学
- 分子生物学
- 基因组学
背景情况:
- 新的细胞功能和蛋白质结构可以从前子混中产生.
- DNA转位子是可移动的遗传元素,可以为基因组进化作出贡献.
研究的目的:
- 研究DNA转位子在提供基因材料的作用.
- 识别转移酶域捕获的实例和融合蛋白的形成.
- 描述新型融合蛋白的功能,特别是KRAB转移酶复合体.
主要方法:
- 在四足动物进化过程中对基因组进行比较分析.
- 转移酶域融合的识别和表征,重点关注替代拼接事件.
- 功能测试以确定已识别的融合蛋白的基因调控活性.
主要成果:
- DNA转位子经常为外体混合提供遗传物质,导致四足动物中至少有94个独立的融合蛋白形成,长达约3.5亿年.
- 转移酶DNA结合域经常与宿主调节域融合,特别是克鲁佩尔相关盒子 (KRAB) 域.
- 鉴定出了四种不同的KRAB转移酶融合蛋白,每个蛋白都能够对特定序列的基因进行抑制.
- 蝙蝠特异性的KRABINER融合蛋白显示出全基因组结合目标转体子,并调节相关基因和cis调节元件.
结论:
- 基因转位子是通过外基因混动进化新蛋白编码基因的重要来源.
- 在基因调节进化过程中重复出现的KRAB转移酶融合蛋白质突出显示了它们的重要性.
- 克拉比纳的例子说明了新型转录因子及其结合点如何从转子介导的基因融合事件中产生.
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