Restoration of potato virus X coat protein capacity for assembly with RNA after His-tag removal

A Recombinant Rotavirus Antigen Based on the Coat Protein of Alternanthera Mosaic Virus

Thanks to their strong immunostimulating properties and safety for humans, plant viruses represent an appropriate basis for the design of novel vaccines. The coat protein of Alternanthera mosaic virus can form virus-like particles that are stable under physiological conditions and have adjuvant properties. This work presents a recombinant human rotavirus A antigen based on the epitope of rotavirus structural protein VP6, using Alternanthera mosaic virus coat protein as a carrier. An expression vector containing the gene of Alternanthera mosaic virus (MU strain) coat protein fused to the epitope of rotavirus protein VP6 was designed. Immunoblot analysis showed that the chimeric protein was effectively recognized by commercial polyclonal antibodies to rotavirus and therefore is a suitable candidate for development of a vaccine prototype. Interaction of the chimeric recombinant protein with the native coat protein of Alternanthera mosaic virus and its RNA resulted in the formation of ribonucleoprotein complexes that were recognized by anti-rotavirus antibodies.

The role of the 5'-cap structure in viral ribonucleoproteins assembly from potato virus X coat protein and RNAs

The potato virus X (PVX) virion can be reconstituted in vitro from the virus coat protein (CP) and RNA; heterologous RNAs may be used as well. In our recent study, structure and properties of cognate and heterologous viral ribonucleoproteins (vRNPs) were demonstrated to be similar to those of native virions. The assembly was found to be initiated at the 5' terminus of an RNA and was not dependent on RNA sequence. The aim of the present study was to search for a signal or an essential structural element that directs packaging of viral genetic material into vRNPs. vRNPs were formed by incubation of the PVX CP with heterologous capped RNAs, their functional fragments lacking the cap structure, as well as the capped and uncapped transcripts corresponding to the 5'-terminal region of the genomic PVX RNA. Experimental data show that the presence of the cap structure at the 5' end of a nucleic acid is an important condition for vRNP assembly from RNA and CP. Presumably, the 5'-cap affects conformational state of the RNA region responsible for the efficient interaction with CP and creates conformational encapsidation signal for vRNP assembly.

Structure, interactions and function of the N-terminus of cardiac myosin binding protein C (MyBP-C): who does what, with what, and to whom?

The thick filament protein myosin-binding protein-C shows a highly modular architecture, with the C-terminal region responsible for tethering to the myosin and titin backbone of the thick filament. The N-terminal region shows the most significant differences between cardiac and skeletal muscle isogenes: an entire Ig-domain (C0) is added, together with highly regulated phosphorylation sites between Ig domains C1 and C2. These structural and functional differences at the N-terminus reflect important functions in cardiac muscle regulation in health and disease. Alternative interactions of this part of MyBP-C with the head-tail (S1-S2) junction of myosin or to actin filaments have been proposed, but with conflicting experimental evidence. The regulation of myosin or actin interaction by phosphorylation of the cardiac MyBP-C N-terminus may play an additional role in length-dependent contraction regulation. We discuss here the evidence for these proposed interactions, considering the required properties of MyBP-C, the way in which they may be regulated in muscle contraction and the way they might be related to heart disease. We also attempt to shed some light on experimental pitfalls and future strategies.

Plant viral epitope display systems for vaccine development

The 'easiest' vaccines, base on production of neutralizing antibodies, have been made. With the emergence of chronic diseases, vaccine developers have understood the importance to trigger an efficient cellular mediated immune response (CTL response) to respond to this medical need. Several options are currently in development and the utilization of plant virus as vaccine platform for the trigger of a CTL response is considered as an interesting avenue. The highly ordered structures of plant viruses are good triggers of the innate immune system, which in turn, is used to initiate an immune response to a vaccine target. It is likely that plant viruses will play an important role in the development of the vaccine of the futures even if there is still several challenges to face.