期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 106, 期 9, 页码 3101-3106出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0900012106
关键词
coevolution; P-TEFb; RNA polymerase II; lentivirus; histone acetyltransferase
资金
- postdoctoral fellowship from the Human Frontier Science Program a
- American Foundation for AIDS Research Mathilde Krim Fellowship in Basic Biomedical Research [106988-43-RFNT]
- National Institutes of Health [AI29135, P50]
HIV-1 Tat enhances viral transcription elongation by forming a ribonucleoprotein complex with transactivating responsive (TAR) RNA and P-TEFb, an elongation factor composed of cyclin T1(CycT1) and Cdk9 that phosphorylates the C-terminal domain of RNA polymerase II. Previous studies have shown that Lys-28 in the activation domain (AD) of Tat is essential for HIV-1 transcription and replication and is acetylated by p300/CBP- associated factor (PCAF), but the mechanistic basis of the Lys- 28 requirement is unknown. Here, we show that Lys- 28 acetylation modulates the affinity and stability of HIV-1 Tat-CycT1-TAR complexes by enhancing an interaction with the CycT1 Tat-TAR recognition motif. High-affinity assembly correlates strongly with stimulation of transcription elongation in vitro and Tat activation in vivo. In marked contrast, bovine lentiviral Tat proteins have evolved a high-affinity TAR interaction that does not require PCAF-mediated acetylation of the Tat AD or CycT1 for RNA binding, whereas HIV-2 Tat has evolved an intermediate mechanism that uses a duplicated TAR element and CycT1 to enhance RNA affinity and consequently transcription activation. The coevolution of Tat acetylation, CycT1 dependence, and TAR binding affinity is seen in viral replication assays using Tat proteins that rely on CycT1 for TAR binding but are acetylation deficient, where compensatory mutations rapidly accrue in TAR to generate high-affinity, CycT1-independent complexes reminiscent of the bovine viruses. Thus, lysine acetylation can be used to modulate and evolve the strength of a viral-host RNA-protein complex, thereby tuning the levels of transcription elongation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据