title: Overexpression of small heat shock protein 21 protects the Chinese oak silkworm Antheraea pernyi against thermal stress.
abstract: Small heat shock proteins (sHSPs) usually act as molecular chaperones to prevent proteins from being denatured in extreme conditions. We first report the sHSP21 gene, named as Ap-sHSP21, in the Chinese oak silkworm Antheraea pernyi (Lepidoptera: Saturniidae). The full-length cDNA of Ap-sHSP21 is 976 bp, including a 5'-untranslated region (UTR) of 99 bp, a 3'-UTR of 316 bp and an open reading frame (ORF) of 561 bp encoding a polypeptide of 186 amino acids. The deduced A. pernyi sHSP21 protein sequence reveals the percent identity is 82-93% in comparison to other sHSPs from insects. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis shows that Ap-sHSP21 expression is higher in testis than that in other examined tissues and significantly up-regulated after heat shock. In addition, prokaryotic expression and purification of the Ap-sHSP21 protein were performed. SDS-PAGE and Western blot analysis demonstrated that a 25 kDa recombinant protein was successfully expressed in Escherichia coli cells and the purified recombinant protein was also confirmed to protect restriction enzymes from thermal inactivation. The expression of Ap-sHSP21 was significantly down-regulated after RNA interference, which was confirmed by qRT-PCR and Western blot analysis. All together, these results suggest that Ap-sHSP21 play a key role in thermal tolerance.
authors.affiliation: College of Life Sciences, Anhui Agricultural University, Hefei 230036, PR China.
authors.forename: Qiu-Ning
authors.initials: QN
authors.lastname: Liu
authors.forename: Bao-Jian
authors.initials: BJ
authors.lastname: Zhu
authors.forename: Li-Shang
authors.initials: LS
authors.lastname: Dai
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Fu
authors.forename: Kun-Zhang
authors.initials: KZ
authors.lastname: Lin
authors.forename: Chao-Liang
authors.initials: CL
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D005260:Female; D050888:Heat-Shock Proteins, Small / Q000302:isolation & purification / Q000378:metabolism*; D006358:Hot Temperature; D019476:Insect Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009036:Moths / Q000378:metabolism*; D010802:Phylogeny; D034622:RNA Interference; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological
chemical_list: D050888:Heat-Shock Proteins, Small; D019476:Insect Proteins
keywords: Antheraea pernyi; Expression; Heat shock protein; Temperature