Abstracts on all topics relating to ranaviruses are being solicited for the 5thISR.

Abstract Submission Date: Friday March 1, 2019

Abstracts should be formatted in accordance with the example below. Presenter’s name should be underlined and text must be a maximum of 250 words (excluding title, authors and affiliations) and in MS Word format.

Submissions should be sent to ranavirussymposium2019@gmail.com

PLEASE INDICATE if you prefer to give an oral presentation or a poster in your email with your submission.

Inquiries about abstract submission should be made to Dr. Duffus and Dr. Forzan, Co-Chairs of the Scientific Committee at ranavirussymposium2019@gmail.com

SAMPLE ABSTRACT:

THE THREE DIMENSIONAL STRUCTURE AND MORPHOGENESIS OF SINGAPORE GROUPER IRIDOVIRUS

1. Tran¹, D-H. Chen², Y. Liu¹,J. Wu³, C. Wah², and C. Hew^{1, 3}

¹Mechanobiology Institute Singapore, National University of Singapore, Singapore. ²Baylor College of Medicine, Houston, TX, USA. ³Department of Biological Sciences, National University of Singapore, Singapore.

Singapore grouper iridovirus (SGIV), a major pathogen in grouper aquaculture, was first isolated in 1998 from brown-spotted grouper. In the past decade, we carried out the viral genomic, transcriptomic, proteomic and lipidomic studies, dissected its molecular compositions and revealed its gene expression profiles. Our results show that the complex virion contains a dsDNA genome of 140,131 bp, at least 44 structural proteins and 220 lipid species. How these molecules are assembled to form a viral particle is unknown. Recent advances in cryoEM/ET technology and computational power have made it possible to examine the structure and morphogenesis of large complex viruses in three dimensions. We took more than 1000 frames with an FEI Titan Krios microscope and selected about 6000 particles for 3D reconstruction. A subnano resolution map was obtained, which reveals: 1) hexamers and pentamers distributed on a T = 247 icosahedral lattice; 2) an irregular lipid bilayer between the capsid shell and viral core; 3) anchor proteins located between the capsid shell and the inner lipid bilayer. High-pressure freezing and freeze substitution were used to prepare SGIV-infected cells for electron microscopy. The viral capsid precursors first appear as closed membrane structures, then develop into headphone shape structures and capsid shells. We identified viral intermediates showing that the viral DNA is packaged into viral capsid during capsid formation. Knockdown of MCP disrupts the viral morphogenesis and diminishes the production of viral particles, while knockdown of viral DNA core protein leads to reduction of viral titer and deformities in viral particles.