MicrobeLibrary – Herpesvirus Replication – Part 2. RNA Transcription in Productive Infection

MicrobeLibrary - Herpesvirus Replication - Part 2. RNA Transcription in Productive Infection

Surprise Me The easy option. Most viral transcripts are not spliced. There is no cure for sexually transmitted viral infections. Arrows in a indicate replication compartments within mitotic cells. Inferred activity of an ectopic ICP0 promoter driving expression of the Cre recombinase and the subsequent Cre-mediated activation of a LacZ reporter from the cellular genome has been used to argue that no more than one-third of latently-infected neurons may have experienced ICP0 expression sometime during the infection [44]. Some viruses, including herpes, change from a spherical shape to a faceted form before they are filled with DNA. Cold sores are not a sign of a recently acquired herpes simplex infection but instead a reactivation of virus particles (virions) already living inside your body.
MicrobeLibrary - Herpesvirus Replication - Part 2. RNA Transcription in Productive Infection

Immediate-early transcripts are transported to the cytoplasm, translated, and the immediate-early proteins migrate back to the nucleus. All further transcription requires the action of these proteins, especially the alpha4 protein, which is a generalized transcription activator working by binding multiple sites on the genome and then interacting with nearby TATA boxes to facilitate assembly of pre-initiation complexes. Whether or not latently infected progenitor cells divide or self-renew (arrow with question mark) is not known, thus the need for (or presence of) replication or partition functions is also unclear. As genomes replicate, they concentrate into discrete compartments and late transcription occurs there. Early transcription is not favored in these compartments and declines with genome replication. Late transcripts also fall into two general groups, leaky-late and strict-late—these differ in the amount of transcription observed prior to genome replication. These are controlled by promoters that have different functional architectures, but which both have sequence elements downstream of the TATA box important in stabilizing the formation of pre-initiation complexes.

To date, the virus cannot be successfully propagated in vitro, although a susceptible cell line with limited viral culturing capability has been reported (26).

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