Shen X, Yu L, Weir J W, Gorovsky M A
Department of Biology, University of Rochester, New York 14627, USA.
Cell. 1995 Jul 14;82(1):47-56. doi: 10.1016/0092-8674(95)90051-9.
We have (separately) disrupted all of the expressed macronuclear copies of the HHO gene encoding macronuclear histone H1 and of the micronuclear linker histone (MLH) gene encoding the protein MicLH in Tetrahymena thermophila. These disruptions are shown to eliminate completely the expression of each protein. Strains without either linker histone grow at normal rates and reach near-normal cell densities, demonstrating that linker histones are not essential for cell survival. Histone H1 knockout (delta H1) cells have enlarged DAPI-stained macronuclei and normal-sized micronuclei, while MicLH knockout (delta MicLH) cells have enlarged micronuclei and normal-sized macronuclei. delta MicLH cells undergo mitosis normally. However, the micronuclear mitotic chromosome structure is less condensed. These studies provide evidence that linker histones are nonessential and are involved in chromatin packaging and condensation in vivo.
我们分别破坏了嗜热四膜虫中编码大核组蛋白H1的HHO基因以及编码蛋白质MicLH的微核连接组蛋白（MLH）基因的所有已表达的大核拷贝。这些破坏作用显示完全消除了每种蛋白质的表达。没有任何一种连接组蛋白的菌株以正常速率生长并达到接近正常的细胞密度，这表明连接组蛋白对于细胞存活并非必不可少。组蛋白H1敲除（ΔH1）细胞的DAPI染色大核增大而微核大小正常，而MicLH敲除（ΔMicLH）细胞的微核增大而大核大小正常。ΔMicLH细胞正常进行有丝分裂。然而，微核有丝分裂染色体结构的凝聚程度较低。这些研究提供了证据，证明连接组蛋白并非必不可少，且在体内参与染色质包装和凝聚。
