A heat shock gene at 14q22: mapping and expression.

Heat shock proteins (HSP) belong to a family of highly homologous proteins that are encoded by several genes and function as protein chaperones. A number of HSP genes have been described in the major histocompatibility complex (MHC) on chromosome 6. We have cloned and mapped one chromosome 14 HSP gene (HSPA2) using a genomic probe (pH2.3) derived from one of the HSP genes present in the MHC, which was previously shown to also detect sequences on chromosome 14. Screening of a chromosome 14-specific cosmid library yielded one relevant clone that contains an HSP-like sequence, showing a high degree of identity with the HSP genes from the MHC and with HSP70.2 (Hspa2) in the mouse. This new HSP gene is expressed abundantly in muscle, heart, oesophagus and brain, and to a lesser extent in testis. Its localization to 14q22 was established by using a somatic cell hybrid panel and FISH analysis. A pentanucleotide repeat motif, showing seven alleles, was also identified in the cosmid clone.