Previous Article | Next Article ![]()
Mol. Cell. Biol., Feb 1995, 1071-1078, Vol 15, No. 2
S Davidson, P Hoj, T Gabriele and RL Anderson
We have identified a murine B-cell lymphoma cell line, CH1, that has a
much-diminished capacity to express increased levels of heat shock proteins
in response to heat stress in vitro. In particular, these cells cannot
synthesize the inducible 72-kDa heat shock protein (HSP72) which is
normally expressed at high levels in stressed cells. We show here that CH1
fails to transcribe HSP72 mRNA after heat shock, even though the heat shock
transcription factor, HSF, is activated correctly. After heat shock, HSF
from CH1 is found in the nucleus and is phosphorylated, trimerized, and
capable of binding the heat shock element. We propose that additional
signals which CH1 cells are unable to transduce are normally required to
activate hsp72 transcription in vitro. Surprisingly, we have found that
when the CH1 cells are heated in situ in a mouse, they show normal
expression of HSP72 mRNA and protein. Therefore, CH1 cells have a
functional hsp72 gene which can be transcribed and translated when the
cells are in an appropriate environment. A diffusible factor present in
ascites fluid is capable of restoring normal HSP72 induction in CH1 cells.
We conclude that as-yet- undefined factors are required for regulation of
the hsp72 gene or, alternatively, that heat shock in vivo causes activation
of hsp70 through a novel pathway which the defect in CH1 has exposed and
which is distinct from that operating in vitro. This unique system offers
an opportunity to study a physiologically relevant pathway of heat shock
induction and to biochemically define effectors involved in the mammalian
stress response.
Copyright © 1995, American Society for Microbiology
In vivo growth of a murine lymphoma cell line alters regulation of expression of HSP72
Peter MacCallum Cancer Institute, Melbourne, Victoria, Australia.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»