Hsp83 sequences including 5' enhancer sequences, the promoter, the 5' untranslated region, the first exon, the intron and the first 111 codons of the open reading frame are fused to a truncated Ecol\lacZ gene (603bp of sequence). The full length 407bp Hsp83 3' untranslated region is fused downstream of the Ecol\lacZ sequence.