Cloning and expression analysis of two small heat shock protein(sHsp) genes from Pyropia haitanensis

Small heat shock proteins(sHsp), representing an important molecular chaperone in eukaryotic cells, play important roles not only in a variety of stress responses, but also in development and signal transduction of normal cell.In this study, based on unigene sequences which were obtained from whole transcriptome sequencing of Pyropia haitanensis, two full-length sHSP genes were obtained by rapid amplification of cDNA ends(RACE)or direct PCR, which named PhHsp22 and PhDnaJ.The full-length cDNA of the PhHsp22 gene comprised 857 nucleotides and contained an open reading frame of 519 bp(GenBank accession:KM102540), encoding a protein of 172 amino acid residues with the predicted molecular weight of 19.1 ku and theoretical isoelectric point of 5.24;the full-length cDNA of the PhDnaJ gene comprised 1 616 nucleotides and contained an open reading frame of 1 290 bp(GenBank accession:KM102541), encoding a protein of 429 amino acid residues with the predicted molecular weight of 46.1 ku and theoretical isoelectric point of 6.43.On the basis of conserved motifs and phylogenetic tree analysis, PhDnaJ belongs to the subfamily of Hsp40.The expressions of the two genes, as measured by real-time quantitative PCR, were significantly induced by high-temperature stress and desiccation stress, and had identical expression patterns:during high-temperature and desiccation stress, the expression levels of the two genes all significantly increased firstly and then decreased.These results suggested that the expressions of PhHsp22 and PhDnaJ genes are feedback regulated by high-temperature and desiccation stresses.