Coronavirus contains three envelope proteins, M, E and S, and a nucleocapsid, which consists of genomic RNA and N protein, within the viral envelope. We studied the macromolecular interactions involved in coronavirus assembly in cells infected with a murine coronavirus, mouse hepatitis virus (MHV). Coimmunoprecipitation analyses demonstrated an interaction between N protein and M protein in inf...

Studies on the virus-cell interactions have proven valuable in elucidating vital cellular processes. Interestingly, certain virus-host membrane interactions found in eukaryotic systems seem also to operate in prokaryotes (Bamford, D.H., M. Romantschuk, and P. J. Somerharju, 1987. EMBO (Eur. Mol. Biol. Organ.) J. 6:1467-1473; Romantschuk, M., V.M. Olkkonen, and D.H. Bamford. 1988. EMBO (Eur. Mol...

Sendai virus nucleocapsid protein NP synthesized in the absence of other viral components assembled into nucleocapsid-like particles. They were identical in density and morphology to authentic nucleocapsids but were smaller in size. The reduction in size was probably due to the fact that they contained RNA only 0.5 to 2 kb in length. Nucleocapsid assembly requires NP-NP and NP-RNA interactions....

Three group A arboviruses, Sindbis (SIN), western (WEE) and eastern equine encephalitis (EEE), were selectively degraded with a nonionic detergent to yield a core particle and a soluble envelope component. Antigenic analysis by using radioimmune precipitation techniques revealed marked antigenic similarity among the core particles of the three viruses. The soluble envelope component exhibited a...

Activation-induced cytidine deaminase (AID) is essential for the somatic hypermutation (SHM) and class-switch recombination (CSR) of Ig genes. The mechanism by which AID triggers SHM and CSR has been explained by two distinct models. In the DNA deamination model, AID converts cytidine bases in DNA into uridine. The uridine is recognized by the DNA repair system, which produces DNA strand breaka...

Hepatitis B virus (HBV) transgenic mice whose hepatocytes replicate the virus at levels comparable to that in the infected livers of patients with chronic hepatitis have been produced, without any evidence of cytopathology. High-level viral gene expression was obtained in the liver and kidney tissues in three independent lineages. These animals were produced with a terminally redundant viral DN...

The alphavirus nucleocapsid core is formed through the energetic contributions of multiple noncovalent interactions mediated by the capsid protein. This protein consists of a poorly conserved N-terminal region of unknown function and a C-terminal conserved autoprotease domain with a major role in virion formation. In this study, an 18-amino-acid conserved region, predicted to fold into an alpha...

Recently, the isolation of a novel virus, GB virus C (GBV-C), associated with cryptogenic hepatitis has been reported. Following the molecular cloning of this virus genome, it became apparent that the genomic sequence did not encode a protein resembling a nucleocapsid or core-like protein similar to those observed in other flaviviruses, pestiviruses, hepatitis C virus (HCV) and GB virus B. Simi...

Isoelectrofocusing of nonionic-detergent-disrupted flaviviruses separated the envelope glycoprotein of 53,000 to 58,000 daltons and the nucleocapsid protein of 14,000 daltons. The envelope protein and nucleocapsid protein were isolated at isoelectric points of pI 7.8 and 10.3, respectively. The antigenic determinants of St. Louis encephalitis, Japanese encephalitis, and dengue virus envelope an...