Recombinant MeV large polymerase protein (aa 2059 - 2183,>95%)

Measles virus (MeV) is a single-stranded, negative-sense RNA virus of the genus Morbillivirus, a family of Paramyxoviridae. It is an acutely contagious infection and a lethal illness for human beings. MeV contains around 15,894 nucleotides, encoding instructions that allow viruses to replicate and express themselves. Measles is transmissible primarily through droplets, has high viral counts, and a long incubation time. MeV's structural proteins – nucleoprotein (N), large polymerase protein (L), phosphoprotein (P), fusion protein (F) and hemagglutinin (H) – contribute to entry, replication, transcription and assembly. MeV contains two non-structural proteins C and V, and the structural proteins that govern the host cell's immune system and replication of the virus. Measles, however highly contagious and fatal (ADEM and subacute sclerosing panencephalitis, or SSPE), is completely preventable by vaccine. Measles worldwide and measles death rates have almost entirely declined since the vaccination was developed in the 1960s. The measles vaccine had wiped out the disease, says the World Health Organization, but still, not all is well – not least in the low- and middle-income world. Measles vaccine with global, highly active live attenuated measles virus (MeV-LV) vaccine. MeV-LV acquires lifetime immune memories against measles virus, which is a natural host to infect Not only do MeV contain structural proteins but also two non-structural proteins, C and V, respectively, which hijack the immune system of the host cell and infect the virus. Although highly contagious and even fatal (most notoriously highly pathogenic acute disseminated encephalomyelitis (ADEM) and subacute sclerosing panencephalitis (SSPE), measles is largely eliminated by vaccination. Disease transmission and death worldwide have declined 50 per cent in the 50 years since measles vaccine was discovered in the 1960s.

Figure 1. Structure of MeV L Protein (Source: Sourimant J, et al., 2016)

RNA-dependent RNA polymerase (RdRP)– L protein, MeV replication and transcription enzyme. This splits the L protein into operative regions like nucleic acid binding sites, polymerase catalytic sites, and mRNA cap-and-methylation sites. The L protein of the RdRP complex binds to the phosphoprotein (P) and nucleoprotein to form the replication and transcription complex. The L protein's function is essential for virus replication and mRNA. MeV genomes are replicated using the encoded RNA-dependent RNA polymerase complex consisting of three proteins: L, P and N. The virus's RdRP complex starts by taking negative-sense RNA as a template and creating positive-sense RNA (mRNA) which is then translated into viral proteins. Genome replication creates new negative-sense RNA from positive-sense RNA. This process takes place in the host cell cytoplasm and needs close collaboration between viral proteins N, P, and L. The L protein, a crucial catalytic enzyme in MeV replication, has various activities. It is responsible for both viral RNA transcription and genome replication. The L protein contains several domains, including the catalytic center responsible for RNA synthesis. The L protein makes sure that RNA is properly elongated and that newly generated RNA chains are stable by interacting with the P and N proteins. Because it interacts with the P and N proteins to produce viral RNA, the L protein is essential for MeV transcription and replication. The stability and effectiveness of freshly produced viral mRNA depend on the L protein's capacity to carry out a number of functions, such as RNA elongation, mRNA capping, and methylation.

Recent research on antiviral therapies for MeV has made some progress. The RdRp complex of MeV is considered a potential drug target, making the development of inhibitors targeting this enzyme complex an important area of study. As a vital component of the RdRp complex, the MeV large polymerase protein (L) plays a central role in genome replication and mRNA transcription, making it an ideal antiviral target. Some researchers have begun to evaluate compounds that bind to the L protein, such as small-molecule inhibitors, which can effectively suppress viral replication and reduce the spread of the measles virus. Additionally, immune therapies targeting MeV are under development. For example, specific anti-measles neutralizing antibodies can enhance the host immune response and reduce viral infectivity, serving as an adjunctive therapeutic approach. The application of monoclonal antibodies against measles and immune enhancers such as interferons also shows preclinical research potential. Ultimately, despite global breakthroughs in measles prevention and control, MeV remains a devastating public health problem. Measles virus (MeV) completes genome replication and transcription through its own RNA-dependent RNA polymerase complex, the large polymerase protein (L) contributing to RNA production, transcription and replication. While measles can sometimes be cured with a vaccine, MeV replication and resistance mechanisms are still major virological themes. Further research indicates that pharmacological discovery of essential viral replication factors (like the L protein) can lead to novel treatment options for measles vaccines. In the future, in addition to increasing vaccination rates, improving the immunogenicity of existing vaccines and developing antiviral drugs against MeV will remain key strategies for controlling the spread of measles and reducing mortality.

Measles Virus L Protein
MeV L Protein
Measles Virus Large Polymerase Subunit
Recombinant MeV Polymerase