Comparison of the structure and expression pattern for a low molecular weight heat-shock protein cDNA clone from Nicotiana tabacum.

We isolated a cDNA clone, named TLHS-1, for a low molecular weight heat-shock protein (LMW HSP) from tobacco. The nucleotide sequence determination of the clone identified an open reading frame for 159 amino acids. To the upstream of the open reading frame, a sequence of 124 nucleotides was determined. To the 3' downstream of the open reading frame, 212 nucleotides were identified which carried a poly(A) tail. A comparison of the open reading frame of TLHS-1 with the previously reported class I LMW HSPs showed a high identity which classified the TLHS-1 as a class I LMW HSP cDNA clone. Reexamination of the amino acid sequences for LMW HSPs including the TLHS-1 argued for the necessity to redraw the consensus region. Six consensus regions were proposed instead of the two consensus regions suggested previously. A RNA blot hybridization for TLHS-1 showed the typical expression pattern of a heat-shock inducible gene from 3 common tobacco cultivars. The genomic DNA blot hybridization for the TLHS-1 gene from the 3 tobacco cultivars showed identical patterns. These results implied that the expression control and structure of the TLHS-1 gene have been well conserved in the tobacco cultivars which are not bred for high temperature stress resistance.