Location: Biological Control of Insects Research
Title: Baculovirus infection induces heat shock response in vivo and in vitro Authors
Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 3, 2011
Publication Date: June 17, 2011
Citation: Breitenbach, J.E., Popham, H.J. 2011. Baculovirus infection induces heat shock response in vivo and in vitro [abstract]. American Society for Virology Meeting. p. 145-146.. Technical Abstract: Baculoviruses are insect pathogens that have been exploited as bio-insecticides for the management of crop pests and for their ability to produce an abundance of heterologous proteins in baculovirus expression systems. Defining the molecular properties of baculovirus strains that broaden host range and increase lethality in their host species, and subsequently combining these traits to enhance the biological utility of baculoviruses would be of substantial public benefit. Recent studies have identified chaperone proteins involved in cellular stress response based on the differences in protein production and in transcriptional profiles of baculovirus-infected permissive cell lines, non-permissive cell lines, and insects infected with baculoviruses. Transcription of the chaperone protein heat shock 70kda (Hsp70) is induced by thermal, chemical, and pathogen-induced cellular stress. Hsp70 functions by binding to and sequestering hydrophobic stretches of amino acids, thereby preventing protein aggregation and allowing re-folding or degradation of nascent polypeptides. Production of a protein bearing sequence homology to Hsp70 was upregulated in baculovirus-infected cells, in agreement with transcriptional studies analyzing the mRNA profiles of infected Heliothis virescens larvae. To further address the hypothesis that chaperone proteins such as Hsp70 play an important role in baculovirus replication, real time PCR studies were conducted to confirm Hsp70 induction in response to in vitro baculovirus infection, to monitor the timing of Hsp70 induction following infection, and to determine the effect that Hsp70 exerts on virus replication and cell fate. New information on factors governing proper folding and trafficking of highly expressed viral proteins may lead to enhancements in baculovirus lethality and greater efficiency of protein production in baculovirus expression systems.