SAMHD1 restricts HIV-1 replication in dendritic and other myeloid cells. SAMHD1 has been shown to possess a dGTP-dependent dNTP triphosphatase (dNTPase) activity and is proposed to inhibit HIV-1 replication by depleting the intracellular dNTP pool. Arguing against a role for SAMHD1 dNTPase in HIV-1 restriction, the phosphorylation of SAMHD1 regulates the restriction activity toward HIV-1 without affecting its ability to decrease cellular dNTP levels. Here, we show that SAMHD1 is a phospho-regulated RNase and that the RNase function is required for HIV-1 restriction. Mutation of the SAMHD1 D137 residue in the allosteric site (SAMHD1D137N) abolishes dNTPase activity but has no effect on RNase activity. This dNTPase-defective SAMHD1D137N mutant is able to restrict HIV-1 infection to nearly the same extent as wild-type SAMHD1. SAMHD1 associates with and degrades the HIV-1 genomic RNA during the early phases of infection. SAMHD1 silencing in macrophages and CD4+ T cells from healthy donors increases HIV-1 RNA stability, thus rendering the cells permissive for HIV-1 infection. Furthermore, the phosphorylation of SAMHD1 at position T592 abolishes the RNase activity toward HIV-1 RNA, and consequently the ability of SAMHD1 to restrict HIV-1 infection, uncovering the phosphorylation of SAMHD1 T592 as a negative regulatory mechanism of RNase activity. Together, our results demonstrate that SAMHD1 is an essential RNase that prevents HIV-1 infection by directly degrading HIV-1 genomic RNA in a phosphorylation-regulated manner. The unique property of SAMHD1 that cleaves HIV-1 genomic RNA with no sequence preferences could be exploited to develop a new class of intervention for error-prone retroviruses. Overall design: Ribosomal RNA-depleted total RNA profiles of mock, SAMHD1 wild type and mutants infected with HIV-1 were examined at the time of 0, 1, 3 h by Illumina Hiseq2500.
The ribonuclease activity of SAMHD1 is required for HIV-1 restriction.
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View SamplesBecause insufficiency of the Runt-related transcription factor 2 (Runx2) limits skeletal growth, there is a great deal of effort to activate Runx2 for clinical use. In this study, we found that MS-275, the class I-specific HDAC inhibitor, activates Runx2 both transcriptionally and translationally. Therefore, we performed NGS analysis to gain accurate patterns of gene expression in mouse calvaria tissue through MS-275 administration. As a result, we could get insight that treatment of MS-275 increases genes related with osteoblast differentiation and cell proliferation, and decreases genes in field of causing apoptosis. Overall design: Mice calvarial mRNA profiles of embryonic day 17.5 wild type (WT) and Runx2+/- mice were generated by deep sequencing using Illumina NextSeq 500. Mice were administered MS-275 or vehicle. Three replicates per group.
An HDAC Inhibitor, Entinostat/MS-275, Partially Prevents Delayed Cranial Suture Closure in Heterozygous Runx2 Null Mice.
Specimen part, Treatment, Subject
View SamplesDownsream of GRID2 in the mouse cerebellum.
Altered Actions of Memantine and NMDA-Induced Currents in a New Grid2-Deleted Mouse Line.
Sex, Age
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