Evolution of HSP70 gene and its implications regarding relationships between archaebacteria,eubacteria, and eukaryotes

The 70-kDa heat-shock protein (HSP70) constitutes the most conserved protein present in all organisms that is known to date. Based on global alignment of HSP70 sequences from organisms representing all three domains, numerous sequence signatures that are specific for prokaryotic and eukaryotic homologs have been identified. HSP70s from the two archaebacterial species examined (viz., Halobacterium marismortui and Methanosarcina mazei) have been found to contain all eubacterial but no eukaryotic signature sequences. Based on several novel features of the HSP70 family of proteins (viz., presence of tandem repeats of a 9-amino-acid [a.a.] polypeptide sequence and structural similarity between the first and second quadrants of HSP70, homology of the N-terminal half of HSP70 to the bacterial MreB protein, presence of a conserved insert of 23–27 a.a. in all HSP70s except those from archaebacteria and gram-positive eubacteria) a model for the evolution of HSP70 gene from an early stage is proposed. The HSP70 homologs from archaebacteria and gram-positive bacteria lacking the insert in the N-terminal quadrants are indicated to be the ancestral form of the protein. Detailed phylogenetic analyses of HSP70 sequence data (viz., by bootstrap analyses, maximum parsimony, and maximum likelihood methods) provide evidence that archaebacteria are not monophyletic and show a close evolutionary linkage with the gram-positive eubacteria. These results do not support the traditional archaebacterial tree, where a close relationship between archaebacterial and eukaryotic homologs is observed. To explain the phylogenies based on HSP70 and other gene sequences, a model for the origin of eukaryotic cells involving fusion between archaebacteria and gram-negative eubacteria is proposed. Correspondence to: R. S. Gupta     

热休克反应中小鼠肾HSP70和乳酸脱氢酶同工酶表达变化的研究

用免疫组织化学和聚丙烯酰胺凝胶同工酶电泳方法研究了小鼠肾在热休克(46℃,30分钟)恢复期(4h和12h)HSP70的表达和乳酸脱氢酶(LDH)同工酶的变化。结果表明:(1)HSP70主要定位于肾小管上皮细胞胞质中,细胞核内未见表达;(2)HSP70免疫阳性反应在肾髓质较肾皮质强,肾小管较肾小球强;(3)热休克诱导小鼠肾LDH同工酶活性增强。提示:LDH同工酶可能对细胞热耐受性的建立有重要作用。     

热休克反应中小鼠心脏HSP70表达的免疫组织化学研究

用免疫组织化学方法研究了小鼠心脏在不同温度（40、41、44、46℃）热休克处理后,各恢复期（2、4、8、12、24小时）HSP70的表达。结果表明,（1）44、46℃热处理能诱导心肌细胞合成HSP70,以46℃为多（P＜0．01）,且于恢复期4－8小时为合成高峰（P＜0．01）。（2）阳性免疫反应定位于心肌细胞质中,核呈阴性反应。提示了心脏有较强的耐热能力。     

Molecular characterization and gene evolution of the heat shock protein 70 gene in snakehead fish with different tolerances to temperature

Temperature tolerances (including lethal limits) and associated rates of thermal acclimation of fish are critical information in predicting fish responses to global climate changes. In this study, a partial sequence of the heat shock protein 70 gene (HSP70) from the fish species Channa striatus was isolated and characterized. Evolutionary process that led to the diversity of HSP70 specific to vertebrates was also analysed. Results revealed that HSP70 is highly homologous in other fish families. The conservation of the HSP 70 gene among fish families could be driven by forces of natural selection due to climatic change. We exposed C. striatus to heat shock (32 °C) and cold shock (16 °C) respectively, in order to examine the differences of temperatures in influencing the expression patterns of HSP70. We revealed that expression of HSP70 was higher at 32 °C than at 16 °C in most of the organs. Specifically, occurrence of chaperone activity of HSP70 was found at low temperature. Therefore, this fish was postulated that to seems to be able to survive at lower temperature compared to higher temperature indicating there is force of natural selection acting towards this HSP 70 gene. This will demonstrate the effect of global warming towards the fish survivability.     

Molecular evolution of the nicotinic acetylcholine receptor: An example of multigene family in excitable cells

An extensive phylogenetic analysis of the nicotinic-acetylcholine-receptor subunit gene family has been performed by cladistic and phenetic methods. The conserved parts of amino acid sequences have been analyzed by CLUSTAL V and PHYLIP software. The structure of the genes was also taken in consideration. The results show that a first gene duplication may have occurred before the appearance of Bilateria. Three subfamilies then appeared: I-the neuronal -bungarotoxin binding-site subunits (7, 8); III-the neuronal nicotinic subunits (2–6, 2–4), which also contain the muscle acetylcholine-binding subunit (1); and IV—the muscle non- subunits (1, , ). The Insecta subunits (subfamily II) could be orthologous to family III and IV. Several tissular switches of expression from neuron to muscle and the converse can be inferred from the extant expression of subunits and the reconstructed trees. The diversification of the neuronal nicotinic subfamily begins in the stem lineage of chordates, the last duplications occurring shortly before the onset of the mammalian lineage. Such evolution parallels the increase in complexity of the cholinergic systems.Abbreviations -Bgt -bungarotoxin - ACh acetylcholine - MP maximum of parsimony - MYA million years ago - NJ neighbor-joining - nAChR nicotinic acetylcholine receptor Correspondence to: N. Le Novère     

HSP70分子伴侣系统研究进展

综述了HSP70分子伴侣系统的晶体结构、功能及作用机理方面的研究进展.HSP70分子伴侣能够帮助细胞内新生蛋白的折叠和跨膜运输、蛋白质多聚体结构的装配和解装配,并能在胁迫下维持蛋白质的特殊构象,防止未折叠的蛋白质变性和使聚集的蛋白质溶解复性.所有这些活性均依赖于ATP调节的HSP70与底物蛋白中的疏水片段的相互作用.     

HSP86 and HSP84 exhibit cellular specificity of expression and co-precipitate with an HSP70 family member in the murine testis

This study extends to the protein level our previous observations, which had established the stage and cellular specificity of expression of hsp86 and hsp84 in the murine testis in the absence of exogenous stress. Immunoblot analysis was used to demonstrate that HSP86 protein was present throughout testicular development and that its levels increased with the appearance of differentiating germ cells. HSP86 was most abundant in the germ cell population and was present at significantly lower levels in the somatic cells. By contrast, the HSP84 protein was detected in the somatic cells of the testis rather than in germ cells. The steady-state levels of HSP86 and HSP84 paralleled the pattern of the expression of their respective mRNAs, suggesting that regulation at the level of translation was not a major mechanism controlling hsp90 gene expression in testicular cells. Immunoprecipitation analysis revealed that a 70-kDa protein coprecipitated with the HSP86/HSP84 proteins in testicular homogenates. This protein was identified as an HSP70 family member by immunoblot analysis, suggesting that HSP70 and HSP90 family members interact in testicular cells. © 1993Wiley-Liss, Inc.     

Seasonal variation in expression pattern of genes under HSP70

Heat shock protein 70 (HSP70) is one of the most abundant and best characterized heat shock protein family that consists of highly conserved stress proteins, expressed in response to stress, and plays crucial roles in environmental stress tolerance and adaptation. The present study was conducted to identify major types of genes under the HSP70 family and to quantify their expression pattern in heat- and cold-adapted Indian goats (Capra hircus) with respect to different seasons. Five HSP70 gene homologues to HSPA8, HSPA6, HSPA1A, HSPA1L, and HSPA2 were identified by gene-specific primers. The cDNA sequences showed high similarity to other mammals, and proteins have an estimated molecular weight of around 70 kDa. The expression of HSP70 genes was observed during summer and winter. During summer, the higher expression of HSPA8, HSPA6, and HSPA1A was observed, whereas the expression levels of HSPA1L and HSPA2 were found to be lower. It was also observed that the expression of HSPA1A and HSPA8 was higher during winter in both heat- and cold-adapted goats but downregulates in case of other HSPs. Therefore, both heat and cold stress induced the overexpression of HSP70 genes. An interesting finding that emerged from the study is the higher expression of HSP70 genes in cold-adapted goats during summer and in heat-adapted goats during winter. Altogether, the results indicate that the expression pattern of HSP70 genes is species- and breed-specific, most likely due to variations in thermal tolerance and adaptation to different climatic conditions.     

Expression of exercise-induced HSP70 in long-distance runner''s leukocytes

This study was designed to investigate the expression of heat shock protein 70 (HSP70), after acute moderate intensity exercise, in human peripheral blood leukocytes of trained runners and untrained controls. Ten male long-distance trained runners (TR) and untrained sedentary control subjects (SED) ran for 1 h at 70% of heart rate reserve (HRR). Basal HSP70 expression in TR was usually lower than that in SED, but basal HSP70 gene expression in TR was usually higher than that in SED. Although expression rates of exercise-induced HSP70 in both groups were similar, levels of HSP70 in SED were significantly higher than in TR. Significant increases in leukocytes, neutrophils, and lymphocytes after exercise were observed in both groups, but there were some differences between groups. We conclude that 1 h treadmill running at 70% HRR intensity is a sufficient stimulus to leukocytosis, neutrocytosis, lymphocytosis, and HSP70 proteins and gene expression in leukocytes. Adaptation to training was observed in TR.     

Detection of sequences homologous to the highly-conserved HSP70 gene of eukaryotes in thermophilic eubacteria and archaebacteria

Abstract The HSP70 genes of eukaryotes show up to 50% nucleotide sequence homology to the dna K gene of Escherichia coli . This extreme structure conservation implies conservation of a function that may be needed by all cells, suggesting that other bacteria may have sequences related to HSP70 and dna K. Amongst other functions, HSP70-like proteins may act to limit thermal protein denaturation. In this study DNA isolated from thermophilic archaebacteria (from the family Desulfurococcus ) and thermophilic eubacteria (from the families Bacillus and Thermus ) was probed with sequences from a heat shock inducible HSP70 gene of the yeast Saccharomyces cerevisiae . Hybridization was detected under conditions of low stringency, indicating the existence of HSP70-related sequences in the thermophilic bacteria studied.     

The induction mechanism of the molecular chaperone HSP70 in the gastric mucosa by Geranylgeranylacetone (HSP-inducer)

To elucidate the induction mechanism of HSP70 by geranylgeranylacetone (GGA), we investigated GGA specific binding proteins using a GGA-affinity column. Alteration of chaperone activity of HSP70 and binding affinity of HSP70 to heat shock factor-1 (HSF-1) was evaluated in the presence or absence of GGA. The binding domain of HSP70 to GGA was also analyzed. A 70-kDa protein eluted by 10 mM GGA from the GGA-affinity column was identical to constitutively expressed HSP70 on immunoblotting. GGA-binding domain of HSP70 was C-terminal of the protein as peptide-binding domain (HSP70C). The chaperone activity of HSP70 and recombinant HSP70C was suppressed by GGA. Furthermore, dissociation of the HSP70 from HSF-1 was observed in the presence of GGA. GGA preferentially binds to the C-terminal of HSP70 which binds to HSF-1. After dissociation of HSP70, free HSF-1 could acquire the ability to bind to HSE (the promoter region of HSP70) gene.     

Intracellular delivery of HSP70 using HIV-1 Tat protein transduction domain

Heat shock protein 70 (HSP70) is an intracellular stress protein that confers cytoprotection to a variety of cellular stressors. Several lines of evidence have suggested that augmentation of the heat shock response by increasing the expression of HSP70 represents a potential therapeutic strategy for the treatment of critically ill patients. The Tat protein of human immunodeficiency virus 1 (HIV-1) has been used previously to deliver functional cargo proteins intracellularly when added exogenously to cultured cells. We generated a Tat-HSP70 fusion protein using recombinant methods and treated HSF -/- cells with either Tat-HSP70 or recombinant HSP70 prior to exposure to hyperoxia or lethal heat shock. We showed that biologically active, exogenous HSP70 can be delivered into cells using the HIV-1 Tat protein, and that the Tat-mediated delivery of HSP70 confers cytoprotection against thermal stress and hyperoxia and may represent a novel approach to augmenting intracellular HSP70 levels.     

The six genes of the Rubisco small subunit multigene family from Mesembryanthemum crystallinum, a facultative CAM plant

The nucleotide sequences of the entire gene family, comprising six genes, that encodes the Rubisco small subunit (rbcS) multigene family in Mesembryanthemum crystallinum (common ice plant), were determined. Five of the genes are arranged in a tandem array spanning 20 kb, while the sixth gene is not closely linked to this array. The mature small subunit coding regions are highly conserved and encode four distinct polypeptides of equal lengths with up to five amino acid differences distinguishing individual genes. The transit peptide coding regions are more divergent in both amino acid sequence and length, encoding five distinct peptide sequences that range from 55 to 61 amino acids in length. Each of the genes has two introns located at conserved sites within the mature peptide-coding regions. The first introns are diverse in sequence and length ranging from 122 by to 1092 bp. Five of the six second introns are highly conserved in sequence and length. Two genes, rbcS-4 and rbcS-5, are identical at the nucleotide level starting from 121 by upstream of the ATG initiation codon to 9 by downstream of the stop codon including the sequences of both introns, indicating recent gene duplication and/or gene conversion. Functionally important regulatory elements identified in rbcS promoters of other species are absent from the upstream regions of all but one of the ice plant rbcS genes. Relative expression levels were determined for the rbcS genes and indicate that they are differentially expressed in leaves.     

植物热激蛋白70的分子作用机理及其利用研究进展

热激蛋白70（heat shock protein 70,HSP70）广泛参与胁迫环境的响应,在诱发人体肿瘤细胞凋亡,增强肿瘤的免疫原性中起着重要作用。然而,植物HSP70的生理功能研究起步较晚,最近的研究发现植物HSP70在细胞内主要参与新生肽的折叠与成熟、损伤蛋白的降解和蛋白运输;植物HSP70在非生物胁迫环境的应答、抗病性及植物发育中起着重要作用。本文从分子生物学角度,系统综述了植物HSP70分子作用机理研究的进展,以及在提高植物抗逆性方面的作用,以期为基因工程方法改良作物抗性提供参考。     

中国辣椒热激蛋白HSP70基因家族分析

以中国辣椒(Capsicum chinense Jacq.)基因组数据为基础, 采用生物信息学方法对中国辣椒HSP70基因家族进行全基因组鉴定分析.结果显示, 中国辣椒全基因共鉴定得到20个HSP70基因, 编码蛋白序列长度为516～854 aa, 分子量大小为56.21～94.26 kD.系统进化分析结果表明, 中国...     

HSP70 polymorphisms in first psychotic episode drug-naïve schizophrenic patients

Aims

The aim of this study is to investigate differences in HSPA8 polymorphisms between first-episode psychotic (FEP) schizophrenic patients and healthy participants after adjustment for temperamental personality traits.

Main methods

This study included fifty drug-naive schizophrenic patients with an FEP and fifty healthy participants who served as controls. Genotyping of HSPA8 polymorphisms was performed in patients and healthy subjects as well. Personality characteristics were assessed using the standardized Greek version of the Alternative Five-Factor Zuckerman–Kuhlman Personality Questionnaire (ZKPQ).

Key findings

Our results showed that FEP patients presented a polymorphism differentiation related to the HSPA8 gene (rs1136141), and a higher frequency of T carriers compared to healthy controls was observed. The HSP8A polymorphism and the levels of Neuroticism as measured by the Alternative Five-Factor ZKPQ were the variables most closely and independently associated with FEP in multiple logistic regression analysis, and the odds of being assessed with a FEP was 2.8 times greater in T carriers compared to non-carriers.

Significance

Present findings indicate a role of HSP8A in FEP and underline the importance of including personality traits in the study of the factors associated with the development of schizophrenia.     

HSP70 interacting protein prevents the accumulation of inclusions in polyglutamine disease1

Heat shock proteins (HSPs) are associated with the proteinaceous inclusions that characterise many neurodegenerative diseases. This suggests they may be associated with disease aetiology and/or represents an attempt to remove abnormal protein aggregates. In this study the adenoviral mediated over‐expression of HSP70 interacting protein (HIP) alone was shown to significantly reduce inclusion formation in both an in vitro model of Spinal Bulbar Muscular Atrophy and a primary neuronal model of polyglutamine disease. Experiments to determine the mechanism of action showed that: denatured luciferase activity (a measure of protein refolding) was not increased in the presence of HIP alone but was increased when HIP was co‐expressed with HSP70 or Heat Shock cognate protein 70 (HSC70); the expression of polyglutamine inclusions in cortical neurons mediated an increase in the levels of HSC70 but not HSP70. Our data suggest that HIP may prevent inclusion formation by facilitating the constitutive HSC70 refolding cycle and possibly by preventing aggregation. HIP expression is not increased following stress and its over‐expression may therefore reduce toxic polyglutamine aggregation events and contribute to an effective therapeutic strategy.     

Progressive strenuous exercise induces the expression of HSP70 in rat skeletal muscles and myocardium

This study investigated the exercise-induced synthesis and accumulation of heat shock protein 70 (HSP70) after progressive strenuous exercise in rat soleus, plantaris, and myocardium. Sprague-Dawley rats were randomly assigned to one of six groups, one control group and five exercise groups, divided by intensity and duration of exercise. Skeletal muscles and heart were dissected immediately after last performance. The levels of HSP70 were analyzed by western blotting using a specific polyclonal antibody. Basal levels of HSP70 in soleus were the highest, and then followed by the myocardium and plantaris, in turn. Progressive strenuous exercise increased accumulation of HSP70 gradually in all three tissues. There were differences in patterns of increase among three tissues.