Question

Genome Type: Double-stranded DNA

Are host proteins needed for replication of the genome?

Are any virus-specific proteins used for replication of the genome? (Provide names

Are any viral proteins needed from replication brought into the cell with the genome?

Answer 1

Viral replication is the formation of biological viruses during the infection process in the target host cells.

Most DNA viruses assemble in the nucleus while most RNA viruses develop solely in cytoplasm.

Double-stranded DNA viruses usually must enter the host nucleus before they are able to replicate.

Multiple proteins are required for DNA replication at a replication fork. Researchers state the following statements regarding this.

• The double-stranded parvovirus B-19 genome contains a single promoter element that recruits cellular transcription factors and RNA polymerase.
• Alternative splicing generates mRNAs coding for the two capsid proteins (VP1 and VP2) and the non-structural protein NS1.
• These viral proteins are all synthesized in the cytoplasm, then imported into the nucleus.
• NS1 is essential for replication of the virus genome, but it is not a DNA polymerase.
• Instead, NS1 acts as an origin recognition protein, which specifically binds to double-stranded virus DNA and allows host DNA polymerase to replicate viral DNA, generating many single-stranded copies of the parvovirus genome.
• Parvovirus B19 can only replicate in actively cycling cells, that express all of the cellular factors necessary for DNA replication.

Both (+) and (-) strand copies are generated, and both can either:

• be converted to double-stranded DNA genomes, which can then be used as templates for virus gene transcription and intermediates for virus genome replication