Fused in sarcoma silences HIV gene transcription and maintains viral latency through suppressing AFF4 gene activation

Background: The human immunodeficiency virus (HIV) cell reservoir is currently a main obstacle towards complete eradication of the virus. This infected pool is refractory to anti-viral therapy and harbors integrated proviruses that are transcriptionally repressed but replication competent. As transcription silencing is key for establishing the HIV reservoir, significant efforts have been made to understand the mechanism that regulate HIV gene transcription, and the role of the elongation machinery in promoting this step. However, while the role of the super elongation complex (SEC) in enhancing transcription activation of HIV is well established, the function of SEC in modulating viral latency is less defined and its cell partners are yet to be identified. Results: In this study we identify fused in sarcoma (FUS) as a partner of AFF4 in cells. FUS inhibits the activation of HIV transcription by AFF4 and ELL2, and silences overall HIV gene transcription. Concordantly, depletion of FUS elevates the occupancy of AFF4 and Cdk9 on the viral promoter and activates HIV gene transcription. Live cell imaging demonstrates that FUS co-localizes with AFF4 within nuclear punctuated condensates, which are disrupted upon treating cells with aliphatic alcohol. In HIV infected cells, knockout of FUS delays the gradual entry of HIV into latency, and similarly promotes viral activation in a T cell latency model that is treated with JQ1. Finally, effects of FUS on HIV gene transcription are also exhibited genome wide, where FUS mainly occupies gene promoters at transcription starting sites, while its knockdown leads to an increase in AFF4 and Cdk9 occupancy on gene promoters of FUS affected genes. Conclusions: Towards eliminating the HIV infected reservoir, understanding the mechanisms by which the virus persists in the face of therapy is important. Our observations show that FUS regulates both HIV and global gene transcription and modulates viral latency, thus can potentially serve as a target for future therapy that sets to reactivate HIV from its latent state.Israel Science Foundation [755/17]; Ben-Gurion University of the Negev, Israel; National Institute of Health [NS082376]; Office of the Director of the NIH [S10OD013237]; NIH [R21AI127274]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Pam18/Tim14–Pam16/Tim16 complex of the mitochondrial translocation motor: The formation of a stable complex from marginally stable proteins

The vast majority of mitochondrial proteins are imported from the cytosol. For matrix-localized proteins, the final step of translocation across the inner membrane is mediated by the mitochondrial translocation motor, of which mhsp70 is a key component. The ATP-dependent function of mhsp70 is regulated by a complex, composed of a J-protein (called Pam18 or Tim14) and a J-like protein (called Pam16 or Tim16), and the nucleotide exchange factor Mge1. In this study, we investigated the structural properties of a recombinant purified Pam18/Tim14–Pam16/Tim16 complex using cross-linking with the bifunctional reagent DSS and CD-spectroscopy. The results of the study show that both Pam18/Tim14 and Pam16/Tim16 are thermally unstable proteins that unfold at very low temperatures (Tm values of 16.5°C and 29°C, respectively). Upon mixing the proteins in vitro, or when both proteins are co-overexpressed in bacteria, Pam18/Tim14 and Pam16/Tim16 form a heterodimer that is thermally more stable than the individual proteins (Tm = 41°C). Analysis of the properties of the complex in GdnHCl shows that dissociation of the heterodimer is the limiting step in achieving full denaturation

Comparison of Platelet-Rich Plasma Treatment and Partial Plantar Fasciotomy Surgery in Patients with Chronic Plantar Fasciitis: A Randomized, Prospective Study

Platelet-Rich Plasma (PRP) injection has become a desirable alternative to Partial Plantar Fasciotomy (PPF) surgery and steroid injection for patients with chronic plantar fasciitis (CPF) due to its potential for shorter recovery times, reduced complications, and similar activity scores. As such, we compared PRP treatment to PPF surgery in patients with CPF. Between January 2015 and January 2017, patients were randomly divided into two groups, a PRP treatment group, and a PPF group. All procedures were performed by a single foot and ankle fellowship-trained specialist surgeon. Visual Analog Score (VAS) and Roles-Maudsley Scale (RM) were collected during the preoperative visit and 3, 6, and 12 months postoperatively. The patients were also closely followed by a physiotherapist. There were 16 patients in each group after four patients refused to participate. Patients in the PPF had low Roles-Maudsley Scale (RM) scores compared to the PRP group one-year after treatment (3.77 vs. 2.72, p p = 0.366). Patients treated with PRP injection reported a significant increase in their activity scores, shorter recovery time, and lower complication rates compared to PPF treatment. Moreover, with respect to existing literature, PRP may be as efficient as steroid injection with lower complication rates, including response to physical therapy. Therefore, PRP treatment may be a viable option before surgery as an earlier line treatment for CPF. Level of Clinical Evidence: II