The class of 90 kDa heat shock proteins (HspSO) is among the most abun
dant heat shock proteins (Hsps) in eukaryotic cells. In vertebrates, H
spSO is encoded by two distinct gene families giving rise to products
of 84 and 86 kDa. In mice the expression of these two genes, hsp84 and
hsp86, vary with respect to each other in responses to stress, and al
so in response to signals for growth and development. Therefore, as a
step towards understanding the molecular basis for the differential re
gulation of these two genes, we have isolated and characterized genomi
c clones of the murine hsp86 gene and its 5' flanking region. The gene
is composed of eleven exons interrupted by 10 introns. The 5' region
contains consensus TATA, several stimulatory protein-1 binding site (S
P1) elements as well as six consensus heat shock elements (HSE) 5' of
the transcription start site. An 806 bp fragment of the 5' promoter re
gion conferred constitutive expression upon a reporter gene and this e
xpression was increased upon heat shock.