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.

Ca 2+ is one of the most universal and versatile signaling molecules and is involved in almost every aspect of cellular processes. Viruses are adept at utilizing the universal Ca 2+ signal to create a tailored cellular environment that meets their own demands. This review summarizes most of the known mechanisms by which viruses perturb Ca 2+ homeostasis and utilize Ca 2+ and cellular Ca 2+ -binding proteins to their benefit in their replication cycles. Ca 2+ plays important roles in virion structure formation, virus entry, viral gene expression, posttranslational processing of viral proteins and virion maturation and release. As part of the review, we introduce an algorithm to identify linear "EF-hand" Ca 2+ -binding motifs which resulted in the prediction of a total of 93 previously unrecognized Ca 2+ -binding motifs in virus proteins. Many of these proteins are nonstructural proteins, a class of proteins among which Ca 2+ interactions had not been formerly appreciated. The presence of linear Ca 2+ -binding motifs in viral proteins enlarges the spectrum of Ca 2+ -virus interplay and expands the total scenario of viral calciomics. (J.J. Yang). for structural integrity or functionality; and (3) critical virus-host interactions depend on cellular Ca 2+ -regulated proteins or pathways. This review, which aims to stimulate future studies on the roles of Ca 2+ in virus infection, is focused on such interplay by highlighting recent discoveries in the biological roles of Ca 2+ in virus infection. 0143-4160/$ -see front matter
Viral calciomics: Interplays between Ca 2+ and virus

The complete nonstructural NS5 gene of Japanese encephalitis virus (JEV) was amplified and cloned into an expression vector. The NS5 protein was expressed in Escherichia coli and purified by His-tag based affinity chromatography. This recombinant NS5 protein exhibited RNA-dependent RNA polymerase (RdRp) activity in vitro in the absence of other viral or cellular factors. The RNA polymerase activity was dependent on divalent cations, and Mn 2 was found to be 20 times more effective than Mg 2 in coordinating the catalytic reaction of RdRp, while Ca 2 inhibited enzyme activity. The optimal reaction conditions for the in vitro RdRp reaction were established. Characterization of the RdRp reaction products demonstrated that the JEV NS5 protein can initiate RNA synthesis through a de novo initiation mechanism in our in vitro reaction system. Comparing the efficiency of different RNA templates, we found that JEV NS5 protein was more efficient in using negative-strand RNA templates, indicating that the JEV NS5 protein is in-volved in regulating the ratio of positive-to negativestrand RNA. Four amino acid sequence motifs crucial for RdRp activity were also identified using site-directed mutagenesis analysis. All substitutions of the conserved residues within these motifs led to a complete inactivation or severe loss of enzyme activity.
Identification and characterization of RNA-dependent RNA polymerase activity in recombinant Japanese encephalitis virus NS5 protein

Porcine epidemic diarrhea virus (PEDV) is a member of the coronaviridae family, which can cause acute and highly contagious enteric disease of swine characterized by severe entero-pathogenic diarrhea in piglets. Currently, the vaccines of PEDV are only partially effective and there is no specific drug available for treatment of PEDV infection. To exploit the possibility of using RNA interference (RNAi) as a strategy against PEDV infection, five shRNA-expressing plasmids targeting the N, M, and S genes of PEDV were constructed and transfected into Vero cells. The cytopathic effect and MTS assays demonstrated that two shRNAs (pSilencer4.1-M1 and pSilencer4.1-N) were capable of protecting cells against PEDV invasion with very high specificity and efficiency. The two shRNA expression plasmids were also able to inhibit the PEDV replication significantly, as shown by detection of virus titers (TCID 50 /mL). A real-time quantitative RT-PCR further confirmed that the amounts of viral RNAs in cell cultures pre-transfected with these two plasmids were reduced by 95.0 %. Our results suggest that RNAi might be a promising new strategy against PEDV infection.
Effective inhibition of porcine epidemic diarrhea virus by RNA interference in vitro