In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

SARS-CoV-2, a member of the coronavirus family, is responsible for the current COVID-19 pandemic. Based on our analysis of hepatitis C virus and coronavirus replication, and the molecular structures and activities of viral inhibitors, we previously demonstrated that three nucleotide analogues inhibit the SARS-CoV RNA-dependent RNA polymerase (RdRp). Here, using polymerase extension experiments, we have demonstrated that the active triphosphate form of Sofosbuvir (a key component of the FDA approved hepatitis C drug EPCLUSA), is incorporated by SARS-CoV-2 RdRp, and blocks further incorporation. Using the same molecular insight, we selected the active triphosphate forms of three other anti-viral agents, Alovudine, AZT (an FDA approved HIV/AIDS drug) and Tenofovir alafenamide (TAF, an FDA approved drug for HIV and hepatitis B) for evaluation as inhibitors of SARS-CoV-2 RdRp. We demonstrated the ability of these three viral polymerase inhibitors, 3'-fluoro-3'-deoxythymidine triphosphate, 3'-azido-3'deoxythymidine triphosphate and Tenofovir diphosphate (the active triphosphate forms of Alovudine, AZT and TAF, respectively) to be incorporated by SARS-CoV-2 RdRp, where they also terminate further polymerase extension. These results offer a strong molecular basis for these nucleotide analogues to be evaluated as potential therapeutics for COVID-19.
Nucleotide Analogues as Inhibitors of SARS-CoV-2 Polymerase

Feline infectious peritonitis virus (FIPV) (Coronaviridae) causes the most lethal viral infection in cats: FIP. The related feline enteric coronavirus (FECV) causes mild enteritis. Why these feline coronaviruses manifest so differently in vivo is not known. In this study, infection kinetics (titres and antigen expression) of FIPV 79-1146, and FECV 79-1683, were determined in peripheral blood monocytes from 3 donor cats and compared to those in Crandell feline kidney (CrFK) cells. The infection kinetics in monocytes were host dependent. Monocytes from 1 cat were resistant to both FIPV-and FECV-infection. Monocytes from the other 2 cats could initially be infected by both FIPV and FECV but FIPV infection was sustained in monocytes of only one cat. FECV-infection was never sustained and viral production was up to 100 times lower than in FIPVinfected monocytes. In CrFK cells, FIPV and FECV infection kinetics did not differ. In monocytes of a larger cat population (n = 19) the 3 infection patterns were also found. Considering all 22 investigated cats, 3/22 were not susceptible for FIPV and FECV. The rest could be infected with FECV and FIPV but 10/22 cats had monocytes that only sustained FIPV infection and 9/22 sustained neither FIPV nor FECV infection. * Both authors contributed equally.
Replication of feline coronaviruses in peripheral blood monocytes

HIV-1 uses a number of means to manipulate the immune system, to avoid recognition and to highjack signaling pathways. HIV-1 infected cells show limited Toll-Like Receptor (TLR) responsiveness via as yet unknown mechanisms. Using biochemical and biophysical approaches, we demonstrate that the trans-membrane domain (TMD) of the HIV-1 envelope (ENV) directly interacts with TLR2 TMD within the membrane milieu. This interaction attenuates TNFa, IL-6 and MCP-1 secretion in macrophages, induced by natural ligands of TLR2 both in in vitro and in vivo models. This was associated with decreased levels of ERK phosphorylation. Furthermore, mutagenesis demonstrated the importance of a conserved GxxxG motif in driving this interaction within the membrane milieu. The administration of the ENV TMD in vivo to lipotechoic acid (LTA)/Galactosamine-mediated septic mice resulted in a significant decrease in mortality and in tissue damage, due to the weakening of systemic macrophage activation. Our findings suggest that the TMD of ENV is involved in modulation of the innate immune response during HIV infection. Furthermore, due to the high functional homology of viral ENV proteins this function may be a general character of viral-induced immune modulation. Citation: Reuven EM, Ali M, Rotem E, Schwarzter R, Gramatica A, et al. (2014) The HIV-1 Envelope Transmembrane Domain Binds TLR2 through a Distinct Dimerization Motif and Inhibits TLR2-Mediated Responses. PLoS Pathog 10(8): e1004248.
The HIV-1 Envelope Transmembrane Domain Binds TLR2 through a Distinct Dimerization Motif and Inhibits TLR2- Mediated Responses