Strict conservation of the retroviral nucleocapsid protein zinc finger is strongly influenced by its role in viral infection processes: Characterization of HIV-1 particles containing mutant nucleocapsid zinc-coordinating sequences
Strict conservation of the retroviral nucleocapsid protein zinc finger is strongly influenced by its role in viral infection processes: Characterization of HIV-1 particles containing mutant nucleocapsid zinc-coordinating sequences
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DOI：
10.1006/viro.1999.9629
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发表时间：
1999-03-30
期刊：
影响因子：
3.7
通讯作者：
Arthur, AO
中科院分区：
文献类型：
--
作者：
Gorelick, RJ;Gagliardi, TD;Arthur, AO
逆转录病毒核衣壳(NC)蛋白含有高度保守的氨基酸序列(-Cys-X-2-Cys-X-4-His-X-4-Cys-)，命名为逆转录病毒(CCHC)锌指。小鼠白血病病毒的NC蛋白含有一个NC锌指，能与金属结合的突变体(CCCC和CCHH)包装了野生型全长病毒RNA，但不具感染性。这些研究扩展到人类免疫缺陷病毒1型(HIV-1)，一种带有两个nc锌离子手指的病毒。用CCHC、CCCC和CCHHzn2+指的组合对HIV-I NC的各个位置的病毒进行了鉴定。突变颗粒含有加工过的病毒蛋白的正常补充。四个突变体包装了大致野生型水平的基因组RNA，而其余的突变体包装了较低水平的基因组RNA。带有突变的C-末端NC指的病毒粒子是一个具有复制能力的有趣的突变体，在NC的N-末端含有CCCC锌2+指，包装了野生型水平的病毒RNA，当在含有HIV-1 LTR/β-半乳糖苷酶结构的表达CD4的HeLa细胞中检测时，显示出类似于野生型水平的感染性。然而，这个特定的突变体在H9细胞中是复制缺陷的；所有其他突变体在8周的检测过程中都是复制缺陷的。在CCCC突变体中可以检测到两个长末端重复的病毒DNA物种，但在任何其他复制缺陷突变体中都没有检测到。这些研究表明，在复制方面，N-末端的锌离子手指位置比C-末端的位置对变化更敏感。此外，逆转录病毒(CCHC)NC锌离子手指是早期感染过程所必需的。维持CCHC NC锌指的进化压力主要取决于它在感染过程中的功能，以及它在基因组包装中的功能。
The retroviral nucleocapsid (NC) protein contains highly conserved amino acid sequences (-Cys-X-2-Cys-X-4-His-X-4-Cys-) designated retroviral (CCHC) Zn2+ fingers. The NC protein of murine leukemia viruses contains one NC Zn2+ finger and mutants that were competent in metal binding (CCCC and CCHH) packaged wild-type levels of full-length viral RNA but were not infectious. These studies were extended to human immunodeficiency virus type 1 (HIV-1), a virus with two NC Zn2+ fingers. Viruses with combinations of CCHC, CCCC, and CCHH Zn2+ fingers in each position of HIV-I NC were characterized. Mutant particles contained the normal complement of processed viral proteins. Four mutants packaged roughly wild-type levels of genomic RNA, whereas the remaining mutants packaged reduced levels. Virions with mutated C-terminal position NC fingers were replication competent One interesting mutant, containing a CCCC Zn2+ finger in the N-terminal position of NC, packaged wild-type levels of viral RNA and showed similar to 5% wild-type levels of infectivity when examined in CD4-expressing HeLa cells containing an HIV-1 LTR/beta-galactosidase construct. However, this particular mutant was replication defective in H9 cells; all other mutants were replication defective over the 8-week course of the assay. Two long terminal repeat viral DNA species could be detected in the CCCC mutant but not in any of the other replication-defective mutants. These studies show that the N-terminal Zn2+ finger position is more sensitive to alterations than the C-terminal position with respect to replication. Additionally, the retroviral (CCHC) NC Zn2+ finger is required for early infection processes. The evolutionary pressure to maintain CCHC NC Zn2+ fingers depends mainly on its function in infection processes, in addition to its function in genome packaging.