通过在Saccharomyces cerevisiae中循环染色体的形成来扩大基因组基因的扩大
1Department of Genetics, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, USA.
Nature
|October 27, 2006
概括
当酵母中基因H2A-H2B基因 (HTA1-HTB1) 被删除时,细胞通过创建一个新的圆形染色体来增强剩余的基因 (HTA2-HTB2),以保持基因组完整性.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 酵母生物学的酵母生物学
背景情况:
- 基质子水平对于基本的细胞过程至关重要,包括转录和染色体分离.
- 在酵母菌 (Saccharomyces cerevisiae) 中,基因组H2A和H2B被两个基因对编码:HTA1-HTB1和HTA2-HTB2.
- 之前已知,当HTA2-HTB2被删除时,HTA1-HTB1的转录补偿会发生.
研究的目的:
- 为了研究超越转录调节的基因组基因剂量补偿的替代机制.
- 阐明当HTA1-HTB1被删除时,基因组基因拷贝号保持的过程.
主要方法:
- 在Saccharomyces cerevisiae中删除HTA1-HTB1基因对.
- 对DNA复制和重组事件的分析,特别是涉及Ty1逆转移子.
- 使用分子技术对新形成的圆形染色体进行表征.
主要成果:
- 删除HTA1-HTB1触发了基因复制数补偿,而不仅仅是转录调整.
- 形成了一个新的,小的圆形染色体,含有HTA2-HTB2,HHT1-HHF1 (基因素H3-H4位置),一个中间体和复制起源.
- 侧面 Ty1 元素之间的重组驱动了这种放大基因组基因含有染色体的形成,在 hta1-htb1Delta 突变中发生的比率更高.
结论:
- 基因组H2A和H2B水平的降低特别刺激通过染色体外DNA对基因组基因的放大.
- 这种基因放大机制确保维护基因组基因剂量和基因组完整性.
- 证明了一种新型的剂量补偿形式,在基因拷贝数层面,以响应基因素耗尽.
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