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Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo.

Cavalieri V, Spinelli G - PLoS ONE (2015)

Bottom Line: Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae.Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae.Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Italy.

ABSTRACT
Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae. Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12.

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Related in: MedlinePlus

TSA treatment and effect on nodal gene expression.(A) Northern blot analysis of total RNA isolated from embryos at the indicated stages exposed or not to TSA 50 nM, and probed with an antisense 32P labelled pRNA against the nodal transcript. The lower panel shows the loading control ribosomal RNAs in the ethidium bromide stained agarose gel. (B) Control and TSA-treated embryos were fixed at the early blastula stage, and analysed by WMISH with a DIG-labelled nodal probe. (C) ChIP-qPCR analysis of the nodal promoter occupancy by H3K9ac. As a negative control, chromatin samples were incubated without antibodies, and negligible amplification was obtained from the corresponding purified DNA. Data are normalized according to the percent of input method, and shown as in Fig 2B and 2C.
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pone.0143860.g003: TSA treatment and effect on nodal gene expression.(A) Northern blot analysis of total RNA isolated from embryos at the indicated stages exposed or not to TSA 50 nM, and probed with an antisense 32P labelled pRNA against the nodal transcript. The lower panel shows the loading control ribosomal RNAs in the ethidium bromide stained agarose gel. (B) Control and TSA-treated embryos were fixed at the early blastula stage, and analysed by WMISH with a DIG-labelled nodal probe. (C) ChIP-qPCR analysis of the nodal promoter occupancy by H3K9ac. As a negative control, chromatin samples were incubated without antibodies, and negligible amplification was obtained from the corresponding purified DNA. Data are normalized according to the percent of input method, and shown as in Fig 2B and 2C.

Mentions: In accordance with this prediction, residual transcription of nodal occurred in TSA-treated blastulae, and it was completely abrogated in embryos at later stages of development, as indicated by Northern blot assay (Fig 3A). Likewise, while nodal transcripts were accumulated exclusively by prospective ventral ectoderm cells of all control embryos at the blastula stage (Fig 3B), by WMISH we did not observe detectable expression of nodal in the vast majority of the TSA-treated embryos at the same stage (86%, n = 182; Fig 3B).


Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo.

Cavalieri V, Spinelli G - PLoS ONE (2015)

TSA treatment and effect on nodal gene expression.(A) Northern blot analysis of total RNA isolated from embryos at the indicated stages exposed or not to TSA 50 nM, and probed with an antisense 32P labelled pRNA against the nodal transcript. The lower panel shows the loading control ribosomal RNAs in the ethidium bromide stained agarose gel. (B) Control and TSA-treated embryos were fixed at the early blastula stage, and analysed by WMISH with a DIG-labelled nodal probe. (C) ChIP-qPCR analysis of the nodal promoter occupancy by H3K9ac. As a negative control, chromatin samples were incubated without antibodies, and negligible amplification was obtained from the corresponding purified DNA. Data are normalized according to the percent of input method, and shown as in Fig 2B and 2C.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664418&req=5

pone.0143860.g003: TSA treatment and effect on nodal gene expression.(A) Northern blot analysis of total RNA isolated from embryos at the indicated stages exposed or not to TSA 50 nM, and probed with an antisense 32P labelled pRNA against the nodal transcript. The lower panel shows the loading control ribosomal RNAs in the ethidium bromide stained agarose gel. (B) Control and TSA-treated embryos were fixed at the early blastula stage, and analysed by WMISH with a DIG-labelled nodal probe. (C) ChIP-qPCR analysis of the nodal promoter occupancy by H3K9ac. As a negative control, chromatin samples were incubated without antibodies, and negligible amplification was obtained from the corresponding purified DNA. Data are normalized according to the percent of input method, and shown as in Fig 2B and 2C.
Mentions: In accordance with this prediction, residual transcription of nodal occurred in TSA-treated blastulae, and it was completely abrogated in embryos at later stages of development, as indicated by Northern blot assay (Fig 3A). Likewise, while nodal transcripts were accumulated exclusively by prospective ventral ectoderm cells of all control embryos at the blastula stage (Fig 3B), by WMISH we did not observe detectable expression of nodal in the vast majority of the TSA-treated embryos at the same stage (86%, n = 182; Fig 3B).

Bottom Line: Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae.Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae.Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Italy.

ABSTRACT
Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 function, either in a spatially-restricted sector or in the whole embryo, specifically rescues nodal transcription in Trichostatin-A-treated larvae. Beyond strengthen the notion that nodal expression is not allowed in the presence of functional Hbox12 in the same cells, these results highlight a critical role of histone deacetylases in regulating the spatial expression of hbox12.

Show MeSH
Related in: MedlinePlus