Dataset Information

Manipulating heat shock factor-1 in Xenopus tadpoles: neuronal tissues are refractory to exogenous expression.

ABSTRACT:

Background

The aging related decline of heat shock factor-1 (HSF1) signaling may be causally related to protein aggregation diseases. To model such disease, we tried to cripple HSF1 signaling in the Xenopus tadpole.

Results

Over-expression of heat shock factor binding protein-1 did not inhibit the heat shock response in Xenopus. RNAi against HSF1 mRNA inhibited the heat shock response by 70% in Xenopus A6 cells, but failed in transgenic tadpoles. Expression of XHSF380, a dominant-negative HSF1 mutant, was embryonic lethal, which could be circumvented by delaying expression via a tetracycline inducible promoter. HSF1 signaling is thus essential for embryonic Xenopus development. Surprisingly, transgenic expression of the XHSF380 or of full length HSF1, whether driven by a ubiquitous or a neural specific promoter, was not detectable in the larval brain.

Conclusions

Our finding that the majority of neurons, which have little endogenous HSF1, refused to accept transgene-driven expression of HSF1 or its mutant suggests that HSF1 levels are strictly controlled in neuronal tissue.

SUBMITTER: Dirks RP

PROVIDER: S-EPMC2854154 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Publications

Manipulating heat shock factor-1 in Xenopus tadpoles: neuronal tissues are refractory to exogenous expression.

Dirks Ron P RP van Geel Remon R Hensen Sanne M M SM van Genesen Siebe T ST Lubsen Nicolette H NH

PloS one 20100413 4

<h4>Background</h4>The aging related decline of heat shock factor-1 (HSF1) signaling may be causally related to protein aggregation diseases. To model such disease, we tried to cripple HSF1 signaling in the Xenopus tadpole.<h4>Results</h4>Over-expression of heat shock factor binding protein-1 did not inhibit the heat shock response in Xenopus. RNAi against HSF1 mRNA inhibited the heat shock response by 70% in Xenopus A6 cells, but failed in transgenic tadpoles. Expression of XHSF380, a dominant- ...[more]

PMID: 20405018

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Project description:When hookworm infective L3s infect their mammalian host, they undergo a temperature shift from that of the ambient environment to that of their endothermic host. Additionally, L3s living in the environment can be exposed to temperature extremes associated with weather fluctuations. The heat shock response (HSR) is a conserved response to heat shock and other stress that involves the expression of protective heat shock proteins (HSPs). The HSR is controlled by heat shock factor-1 (HSF-1), a conserved transcription factor that binds to a heat shock element in the promoter of HSPs, causing their expression. HSF-1 is negatively regulated in part by a HSF binding protein (HSB-1) that binds to and removes HSF-1 trimers bound to HSP gene promoters, resulting in attenuation of the HSR. Herein we describe an HSB-1 orthologue, Ac-HSB-1, from the hookworm Ancylostoma caninum. The Ac-hsb-1 cDNA encodes a 79 amino acid protein that is 71% identical to the Caenorhabditis elegans HSB-1, and is predicted to share the characteristic coiled-coil structural motif comprised of two interacting alpha helices. Recombinant Ac-HSB-1 immunoprecipitated Ce-HSF-1 expressed in mammalian cells that had been heat shocked for 1h at 42°C, but not from cells incubated at 37°C, indicating that HSB-1 only bound to the active DNA binding form of HSF-1. Expression of Ac-hsb-1 transcripts decreased following 1h of heat shock, but increased when L3s were incubated at 37°C for 1h. Activation of hookworm L3s induces a five-sixfold increase in Ac-hsb-1 expression that peaks at 12h, coincident with L3 feeding, but that subsequently decreases to two-threefold above control at 24h. Recombinant Ac-HSB-1 immunoprecipitates greater amounts of 70 and 40kDa proteins from extracts of activated L3s than from non-activated L3s. We propose that an increase in Ac-hsb-1 levels early in activation allows feeding to resume, but that a subsequent decrease in expression permits a HSR that protects non-developing L3s at host-like temperatures. Further investigations of the HSR will clarify the role of HSB-1 and HSF-1 in hookworm infection.

Dataset Information

Manipulating heat shock factor-1 in Xenopus tadpoles: neuronal tissues are refractory to exogenous expression.

Background

Results

Conclusions

Publications

Manipulating heat shock factor-1 in Xenopus tadpoles: neuronal tissues are refractory to exogenous expression.

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