Disclosed herein are nucleic acid constructs comprising a replication defective Zika virus vector and one or more coronavirus sequences and compositions thereof. The constructs relates to compositions and methods for inducing an immune response against coronavirus antigens due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) outbreak. The results herein indicate that these coronavirus constructs are safe and will induce an immune response that may provide protection against coronaviruses.

In certain aspects, the present disclosure provides nucleic acid molecules containing ribozyme catalytic cores for production of circularized RNA containing a nucleic acid sequence of interest, as well as methods of preparation and methods of use.

The invention provides compositions and methods that are useful for screening gene regulatory elements for cell type-specific expression in vivo.

The present invention relates to a hepatitis A virus production method and hepatitis A virus produced according to the method, and, more specifically, to: a hepatitis A virus production method and hepatitis A virus produced according to the method, the method comprising the step of infecting a host cell with a virus obtained by transforming a host cell with a vector comprising an expression cassette, which comprises a hepatitis A virus gene, for hepatitis A virus preparation, and subculturing same.

The invention provides polynucleotide constructs for the regulation of gene expression by aptamer-based modulation of self-cleaving ribozymes and methods of using the constructs to regulate gene expression in response to the presence or absence of a ligand that binds the aptamer. The invention further provides methods for making and using riboswitches that decrease target gene expression in response to an aptamer ligand as well as riboswitches that increase target gene expression in response to an aptamer ligand.

The technology described herein is directed to Aptamer and Ribozyme Equilibrium Shifting (ARES) regions, including ON-switches and OFF-switches, which can be harnessed to regulate the stability of RNA molecules. Also described herein are compositions comprising such RNA molecules and methods of using them to regulate translation of cargo polypeptides.

Unlike DNA, mRNA has the advantage of enabling transient expression of a desired protein directly in the cytoplasm without having to enter the nucleus, and thus attempts to use mRNA vaccines are actively underway. However, mRNA has lower structural stability than DNA, and thus has limitations with respect to industrial application. Therefore, the present invention relates to a technology for remarkably improving intracellular stability and biogenesis of mRNA. An mRNA stabilization method and an mRNA stabilization composition, of the present invention, have the excellent effects of enhancing target nucleic acid stabilization and target protein expression in mRNA vaccines and the like, and thus are expected to be widely used in the health/medical field.

The present invention relates to a hepatitis A virus production method and hepatitis A virus produced according to the method, and, more specifically, to: a hepatitis A virus production method and hepatitis A virus produced according to the method, the method comprising the step of infecting a host cell with a virus obtained by transforming a host cell with a vector comprising an expression cassette, which comprises a hepatitis A virus gene, for hepatitis A virus preparation, and subculturing same.