Molecular chaperones have long been understood
to be preferentially transcribed in response to multiple
perturbations of the cellular homeostasis. In this study,
several polymorphisms in the gene encoding the inducible
form of the cytoplasmic Hsp90 (HSP90AA1) were
addressed in 24 sheep breeds reared in different climatic
regions of Europe, Africa, and Asia. Significant differences
in the genotype frequencies for a C/G single nucleotide
polymorphism (SNP) located at position −660 in the
HSP90AA1 5′flanking region were found between the
different breeds. Regression analyses reflected significant
correlations (from 0.41 to 0.62) between the alternative
genotypes of this polymorphism and several climatic and
geographic variables characteristic of the regions where
these breeds are reared. Real-time analysis revealed that
animals bearing the CC−660 genotype presented higher
expression levels than those presenting the CG−660 or
GG−660 in summer, but not in spring. Mutation at −660
site seems to affect HSP90AA1 transcription rates which
could have important effects on the adaptation to different
environmental conditions in sheep. Thus, the variability
found in the genotype frequencies for the SNP at −660 in
the ovine HSP90AA1 locus could be the result of the
different environmental pressures occurring in the regions
where these breed are maintained.AGRAMA breeders association, CSIC-León
(Spain), CITA-Aragón (Spain), Centro Nacional de Referencia de EETs (Spain), Universidad de Zaragoza (Spain), NEIKER-Vitoria
(Spain), Centro de Investigación La Orden-Valdesequera Junta de Extremadura (Spain), Dr. Julián Garde from the Universidad de Castilla-La Mancha (Spain), INIA-Madrid (Spain), and Dr Maziek
Murawski from the University of Cracow (Poland) have provided biological samples. We are also very grateful to Dr. Jaime Cubero
from INIA for his logistic support and to Helen Neumann for the English corrections. RTA2006-00104-00-00 and RZ2004-28 INIA
projects have provided refunding to develop the experimental work
