Antipathogen Genes Research Articles

RICK activates a NF-kappaB-dependent anti-human cytomegalovirus response.

The adapter kinase receptor interacting protein-like interacting caspase-like apoptosis regulatory protein kinase (RICK, also called RIP2 and CARDIAK) was found to be elevated at both the protein and RNA levels during human cytomegalovirus (HCMV) replication, suggesting either that the virus may require RICK for replication or that RICK is part of an unsuccessful host attempt to inhibit HCMV replication. It is demonstrated here that forced expression of RICK in either a kinase active or inactive form activates nuclear factor (NF)-kappaB by means of its intermediate domain and potently blocks HCMV replication in human fibroblasts. Importantly, NF-kappaB activation, which exerted a modestly positive effect on the early phase of infection, clearly had a strongly negative impact during later viral steps. A stable inhibitor of NF-kappaB (IkappaB) reverses the RICK inhibitory effect, and activation of NF-kappaB by IkappaB kinase beta expression is inhibitory to HCMV, demonstrating that NF-kappaB activation is part of a potent anti-HCMV response. Supernatant transfer experiments identified interferon-beta as a downstream component of the RICK inhibitory pathway. RICK expression was found to synergize with HCMV infection in the induction of interferon-beta expression. This study identifies an endogenous RICK-activated, NF-kappaB- and interferon-beta-dependent antiviral pathway that is either inhibited or faulty under normal HCMV replication conditions; efforts to bolster this pathway may lead to novel anti-viral approaches.

Genetics of mosquito vector competence.

Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality.