Axel Boldt wrote:
> 1) Is the HIV provirus always integrated at the same spot in the host
> cell's genome? If yes, where?
>> 2) What exactly causes the provirus to become active and produce new
> particles -- is it the activation of the T-cell by antigen?
HIV integrates into AT-rich regions of the cell's genome, which have the
same base composition as itself (AT-rich). Whether this is necessary for
the initial integration, or subsequent survival in the genome, is not
clear. (Base composition is the "accent" of DNA, which may "speak" with
an AT-rich, or a GC-rich accent. Just as someone's accent may sometimes
put you off proposing union with that person, so DNA's accent in a
particular region of the genome may put off HIV integration.)
Most T cells are "latent" in the G-zero stage of the cell cycle. When
the cells are activated by antigen they move into the cell cycle and
proliferate. Under these conditions, just right for HIV replication, the
virus seizes the opportunity and activates, transcribing RNA copies
which are coated to form viral particles.
Sincerely, Donald Forsdyke, Discussion Leader, Bionet immunology
