title: Expression analysis of HSP70 in the testis of Octopus tankahkeei under thermal stress.
abstract: The gene encoding heat shock protein 70 (HSP70) was identified in Octopus tankahkeei by homologous cloning and rapid amplification of cDNA ends (RACE). The full-length cDNA (2471 bp) consists of a 5'-untranslated region (UTR) (89 bp), a 3'-UTR (426 bp), and an open reading frame (1956 bp) that encodes 651 amino acid residues with a predicted molecular mass of 71.8 kDa and an isoelectric point of 5.34. Based on the amino acid sequence analysis and multiple sequence alignment, this cDNA is a member of cytoplasmic hsp70 subfamily of the hsp70 family and was designated as ot-hsp70. Tissue expression analysis showed that HSP70 expression is highest in the testes when all examined organs were compared. Immunohistochemistry analysis, together with hematoxylin-eosin staining, revealed that the HSP70 protein was expressed in all spermatogenic cells, but not in fibroblasts. In addition, O. tankahkeei were heat challenged by exposure to 32 °C seawater for 2 h, then returned to 13 °C for various recovery time (0-24 h). Relative expression of ot-hsp70 mRNA in the testes was measured at different time points post-challenge by quantitative real-time PCR. A clear time-dependent mRNA expression of ot-hsp70 after thermal stress indicates that the HSP70 gene is inducible. Ultrastructural changes of the heat-stressed testis were observed by transmission electron microscopy. We suggest that HSP70 plays an important role in spermatogenesis and testis protection against thermal stress in O. tankahkeei.
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: Ling-Li
authors.initials: LL
authors.lastname: Long
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: Ying-Li
authors.initials: YL
authors.lastname: Han
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Sheng
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Du
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: You-Fa
authors.initials: YF
authors.lastname: Wang
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China. Electronic address: zhujunquan@nbu.edu.cn.
authors.forename: Jun-Quan
authors.initials: JQ
authors.lastname: Zhu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA; D018840:HSP70 Heat-Shock Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D049831:Octopodiformes / Q000502:physiology*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D012623:Seawater; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D013696:Temperature; D013737:Testis / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D004247:DNA
keywords: HSP70; Octopus tankahkeei; Spermatogenesis; Testis; Thermal stress