Previous Article | Next Article ![]()
Mol. Cell. Biol., Mar 1995, 1343-1352, Vol 15, No. 3
M Sigvardsson, M Bemark and T Leanderson
The SP6 kappa-promoter pentadecamer (pd) element was found to be unable to
stimulate transcription when present in one copy as the only promoter
element in a minimal promoter but showed weak stimulatory activity when
present as a multimer (four copies). One copy of the pd element acted
synergistically with an octamer element, but not with a SP1 site, to
stimulate transcription. The effect was orientation dependent with regard
to the pd element. Gel shift analysis showed that pd-binding proteins were
expressed in transformed as well as nontransformed B lymphocytes,
irregardless of their differentiation stage, and in HeLa cells. Two major
complexes, binding to different sites within the pd element, were observed
in gel shifts. A low- molecular-weight form dominated in resting cells,
while a higher- molecular-weight form appeared after mitogenic stimulation.
Southwestern analysis showed that the low-molecular-weight pd-binding
protein had a molecular mass of 35 kDa, which was confirmed by
fractionation by denaturating polyacrylamide gel electrophoresis and
molecular sieving. The higher-molecular-weight complex was sensitive to
detergent treatment, while the low-molecular-weight complex was not.
Mutation analysis showed that the two pd-binding complexes interacted with
distinct sites within the element and that dual occupancy was required for
functional activity. The functional synergy between the pd element and the
octamer was more pronounced in plasmacytomas than in B- cell lymphomas.
Copyright © 1995, American Society for Microbiology
Pentadecamer-binding proteins: definition of two independent protein- binding sites needed for functional activity
Immunology Unit, Lund University, Sweden.
This article has been cited by other articles:
| J. Bacteriol. | J. Virol. | Eukaryot. Cell |
|---|
| Microbiol. Mol. Biol. Rev. | Clin. Vaccine Immunol. | All ASM Journals |
|---|