The Ebola and Marburg viruses, both members of the filovirus family, wreak havoc on host cells with just seven open reading frames (ORFs) encoded by a 19-kilobase RNA genome. But a comprehensive examination of viral messenger RNAs, published yesterday (November 4) in mBio, has uncovered hidden variation in some of the transcripts produced by Ebola and Marburg when they infect animal cells.
Researchers at the Icahn School of Medicine at Mount Sinai in New York City and their colleagues infected monkey and human cell lines with both viruses, and performed Illumina sequencing on RNA isolated from the cells at different time points after infection.
An analysis of the viral transcripts identified sites where the viral polymerase inserted nucleotides, likely leading to previously undescribed proteins. The messenger RNA (mRNA) encoding the Ebola glycoprotein was the most commonly edited, while transcripts for the Marburg virus nucleoprotein and polymerase were also altered.
Investigating variability in the Ebola glycoprotein could be particularly important for the development of vaccines and treatments, since this protein plays a role in virulence and mediates the attachment of the virus to host cells.
“The bottom line is we know these changes occur but we don’t yet know what it really means in the biology of the virus,” study coauthor Christopher Basler said in a press release. Basler added that the life cycles of filoviruses are not well understood, “so we need a complete description of how they grow to develop new strategies used to treat the infections.”