The invention provides a novel post-transcriptional regulatory element that can
function as an RNA nucleo-cytoplasmic transport element. The invention also provides
for an attenuated HIV-1 hybrid virus for use as a vaccine and a kit incorporating
the hybrid virus. The kit also includes instructional material teaching the use
of the vaccine, where the instructional material indicates that the vaccine is
used for the prophylaxis or amelioration of HIV-1 infection in a mammal; that the
vaccine is to be administered to a mammal in a therapeutically effective amount
sufficient to express a viral protein; where the vaccine will not cause clinically
significant CD4+ cell depletion; and, the expression of the viral protein
elicits an immune response to the attenuated HIV-1 virus. The invention further
provides for a method for screening for post-transcriptional RNA nucleo-cytoplasmic
transport element (NCTE) binding proteins.
