9 research outputs found
Efficient expression of nuclear transgenes in the green alga Chlamydomonas: synthesis of an HIV antigen and development of a new selectable marker
Dissecting the contributions of GC content and codon usage to gene expression in the model alga Chlamydomonas reinhardtii
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An epigenetic gene silencing pathway selectively acting on transgenic DNA in the green alga Chlamydomonas.
Silencing of exogenous DNA can make transgene expression very inefficient. Genetic screens in the model alga Chlamydomonas have demonstrated that transgene silencing can be overcome by mutations in unknown gene(s), thus producing algal strains that stably express foreign genes to high levels. Here, we show that the silencing mechanism specifically acts on transgenic DNA. Once a permissive chromatin structure has assembled, transgene expression can persist even in the absence of mutations disrupting the silencing pathway. We have identified the gene conferring the silencing and show it to encode a sirtuin-type histone deacetylase. Loss of gene function does not appreciably affect endogenous gene expression. Our data suggest that transgenic DNA is recognized and then quickly inactivated by the assembly of a repressive chromatin structure composed of deacetylated histones. We propose that this mechanism may have evolved to provide protection from potentially harmful types of environmental DNA
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Publisher Correction: An epigenetic gene silencing pathway selectively acting on transgenic DNA in the green alga Chlamydomonasis.
In the original version of this Article, the y-axis label of Fig. 1d was incorrectly given as “Relative H3Ac/H3 levels” and should read “Relative H4Ac/H3 levels”. In addition, the probe target in the left panel of Figure 1f was misspelled as “Guliver” and should read “Gulliver”. Furthermore, the last label of the diagram on the top of Fig. 2c was given incorrectly as “PF26” and should read “PF25”. Moreover, the label of the branch pointed by the arrow symbol in cluster II of the phylogenetic tree in Fig. 3c was incorrectly labelled as “CrSRTb” and the correct label is “CrSRTB”. These errors have been corrected in both the PDF and HTML versions of the Article
Publisher Correction: An epigenetic gene silencing pathway selectively acting on transgenic DNA in the green alga Chlamydomonasis
A Correction to this paper has been published: https://doi.org/10.1038/s41467-020-20623-
Sulfur deficiency-induced genes affect seed protein accumulation and composition under sulfate deprivation
Sulfur deficiency-induced proteins SDI1 and SDI2 play a fundamental role in sulfur homeostasis under sulfate-deprived conditions (−S) by downregulating glucosinolates. Here, we identified that besides glucosinolate regulation under –S, SDI1 downregulates another sulfur pool, the S-rich 2S seed storage proteins in Arabidopsis (Arabidopsis thaliana) seeds. We identified that MYB28 directly regulates 2S seed storage proteins by binding to the At2S4 promoter. We also showed that SDI1 downregulates 2S seed storage proteins by forming a ternary protein complex with MYB28 and MYC2, another transcription factor involved in the regulation of seed storage proteins. These findings have significant implications for the understanding of plant responses to sulfur deficiency