N. Marmiroli et al., IDENTIFICATION, CHARACTERIZATION, AND ANALYSIS OF CDNA AND GENOMIC SEQUENCES ENCODING 2 DIFFERENT SMALL HEAT-SHOCK PROTEINS IN HORDEUM-VULGARE, Genome, 36(6), 1993, pp. 1111-1118
In vitro translation of mRNAs prepared from barley (Hordeum vulgare) s
eedlings (cv. Onice) exposed at 40 degrees C directed the synthesis of
major heat shock proteins (HSPs) with molecular masses of 80-90, 70,
42 and 16-22 kDa. A cDNA library prepared from the 40 degrees C mRNAs
and screened by differential hybridization led to the isolation of hea
t shock specific sequences. One of these (Hv hsp18) was confirmed by h
ybrid-arrested and hybrid-released translation as encoding for an 18-k
Da HSP. The barley hsp18 sequence has an open reading frame encoding a
160 amino acid residue 18-kDa protein that is 63% identical to wheat
16.9-kDa HSP (clone C5-8), 54% identical to soybean (Glycine max) 17.5
-kDa HSP, and 49% identical to Arabidopsis thaliana 17.6-kDa HSP Lower
similarities were found with class II plant small HSPs such as soybea
n 17.9-kDa HSP (27%), Pisum sativum 17.7-kDa HSP (30%), wheat (Triticu
m aestivum) 17.3-kDa HSP (clone Ta hsp 17.3) (30%), and with animal sm
all HSPs and alpha-crystallins. The Hv hsp18 sequence was used to pick
up Hv hsp17 genomic sequence encoding for another class I 17-kDa HSP
By computer analysis of the nucleotide sequence the TATA box, two heat
shock promoter elements, a metal-ion response element, and the polyad
enylation signals were identified. Barley HSP18 has an additional cyst
eine-rich region when compared with HSP17 mapping at the carboxy termi
nal end.