Induction of TSP1 gene expression by heat shock is mediated via an increase in mRNA stability

Thrombospondin-1 (TSP1) expression has previously been shown to be regulated primarily at the level of transcription. In the present study, transcriptional control was not involved in the induction of TSP1 by heat shock. In contrast, heat shock caused significant stabilization of TSP1 mRNA. Fusion of the 3′-untranslated region (UTR) of TSP1 mRNA, with a reporter gene, increased the stability of the reporter transcript by heat shock. Furthermore, we identified a putative region from 968 to 1258 from the stop codon in the TSP1 3′-UTR, involved in the stability by heat shock. Thus, the induction of TSP1 by heat shock may occur through a post-transcriptional mechanism.