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The arabidopsis DNA polymerase δ has a role in the deposition of transcriptionally active epigenetic marks, development and flowering.

Iglesias FM, Bruera NA, Dergan-Dylon S, Marino-Buslje C, Lorenzi H, Mateos JL, Turck F, Coupland G, Cerdán PD - PLoS Genet. (2015)

Bottom Line: Here we identify such a mutant which is also thermosensitive.Surprisingly, high expression of SEP3 in vascular tissue promoted FLOWERING LOCUS T (FT) expression, forming a positive feedback loop with SEP3 and leading to early flowering and curly leaves phenotypes.These results strongly suggest that the DNA polymerase δ is required for the proper establishment of transcriptionally active epigenetic marks and that its failure might affect development by affecting the epigenetic control of master genes.

View Article: PubMed Central - PubMed

Affiliation: Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.

ABSTRACT
DNA replication is a key process in living organisms. DNA polymerase α (Polα) initiates strand synthesis, which is performed by Polε and Polδ in leading and lagging strands, respectively. Whereas loss of DNA polymerase activity is incompatible with life, viable mutants of Polα and Polε were isolated, allowing the identification of their functions beyond DNA replication. In contrast, no viable mutants in the Polδ polymerase-domain were reported in multicellular organisms. Here we identify such a mutant which is also thermosensitive. Mutant plants were unable to complete development at 28°C, looked normal at 18°C, but displayed increased expression of DNA replication-stress marker genes, homologous recombination and lysine 4 histone 3 trimethylation at the SEPALLATA3 (SEP3) locus at 24°C, which correlated with ectopic expression of SEP3. Surprisingly, high expression of SEP3 in vascular tissue promoted FLOWERING LOCUS T (FT) expression, forming a positive feedback loop with SEP3 and leading to early flowering and curly leaves phenotypes. These results strongly suggest that the DNA polymerase δ is required for the proper establishment of transcriptionally active epigenetic marks and that its failure might affect development by affecting the epigenetic control of master genes.

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FT is required for gis5 early flowering.(A-B) Loss of FT function suppresses most of gis5 early flowering phenotype. Plants of the genotypes indicated on the abscissa were grown under LD (A) or SD (B) at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype. (C-D) The increase in FT expression is temperature-dependent in gis5 mutants. WT and gis5 mutant plants were grown for 10 days under continuous light at either 18°C or 24°C (C), or for 21 days under SD at either temperature. Plants grown under SD were harvested at the end of the photoperiod. Total RNA was extracted and FT transcripts quantitated by qRT-PCR relative to UBQ10 mRNA. Bars represent the mean ±SEM of 3 independent biological replicates, each replicate analyzed in triplicate. (E) Phloem specific FT expression is required for gis5 early flowering. gis5 mutants were crossed to transgenic lines bearing artificial microRNAs against FT expressed under specific promoters (FD for apical meristem specific expression, SUC2 for phloem specific expression and 35S for high and constitutive expression [3]. These genotypes and the corresponding controls (indicated on the abscissa) were grown under LD at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype.
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pgen.1004975.g004: FT is required for gis5 early flowering.(A-B) Loss of FT function suppresses most of gis5 early flowering phenotype. Plants of the genotypes indicated on the abscissa were grown under LD (A) or SD (B) at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype. (C-D) The increase in FT expression is temperature-dependent in gis5 mutants. WT and gis5 mutant plants were grown for 10 days under continuous light at either 18°C or 24°C (C), or for 21 days under SD at either temperature. Plants grown under SD were harvested at the end of the photoperiod. Total RNA was extracted and FT transcripts quantitated by qRT-PCR relative to UBQ10 mRNA. Bars represent the mean ±SEM of 3 independent biological replicates, each replicate analyzed in triplicate. (E) Phloem specific FT expression is required for gis5 early flowering. gis5 mutants were crossed to transgenic lines bearing artificial microRNAs against FT expressed under specific promoters (FD for apical meristem specific expression, SUC2 for phloem specific expression and 35S for high and constitutive expression [3]. These genotypes and the corresponding controls (indicated on the abscissa) were grown under LD at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype.

Mentions: To evaluate which flowering pathways are affected by the gis5 mutation, we investigated the epistatic relationships between gis5 and those mutations affecting the photoperiod, autonomous and vernalization pathways (Fig. 4A-B).


The arabidopsis DNA polymerase δ has a role in the deposition of transcriptionally active epigenetic marks, development and flowering.

Iglesias FM, Bruera NA, Dergan-Dylon S, Marino-Buslje C, Lorenzi H, Mateos JL, Turck F, Coupland G, Cerdán PD - PLoS Genet. (2015)

FT is required for gis5 early flowering.(A-B) Loss of FT function suppresses most of gis5 early flowering phenotype. Plants of the genotypes indicated on the abscissa were grown under LD (A) or SD (B) at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype. (C-D) The increase in FT expression is temperature-dependent in gis5 mutants. WT and gis5 mutant plants were grown for 10 days under continuous light at either 18°C or 24°C (C), or for 21 days under SD at either temperature. Plants grown under SD were harvested at the end of the photoperiod. Total RNA was extracted and FT transcripts quantitated by qRT-PCR relative to UBQ10 mRNA. Bars represent the mean ±SEM of 3 independent biological replicates, each replicate analyzed in triplicate. (E) Phloem specific FT expression is required for gis5 early flowering. gis5 mutants were crossed to transgenic lines bearing artificial microRNAs against FT expressed under specific promoters (FD for apical meristem specific expression, SUC2 for phloem specific expression and 35S for high and constitutive expression [3]. These genotypes and the corresponding controls (indicated on the abscissa) were grown under LD at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
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pgen.1004975.g004: FT is required for gis5 early flowering.(A-B) Loss of FT function suppresses most of gis5 early flowering phenotype. Plants of the genotypes indicated on the abscissa were grown under LD (A) or SD (B) at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype. (C-D) The increase in FT expression is temperature-dependent in gis5 mutants. WT and gis5 mutant plants were grown for 10 days under continuous light at either 18°C or 24°C (C), or for 21 days under SD at either temperature. Plants grown under SD were harvested at the end of the photoperiod. Total RNA was extracted and FT transcripts quantitated by qRT-PCR relative to UBQ10 mRNA. Bars represent the mean ±SEM of 3 independent biological replicates, each replicate analyzed in triplicate. (E) Phloem specific FT expression is required for gis5 early flowering. gis5 mutants were crossed to transgenic lines bearing artificial microRNAs against FT expressed under specific promoters (FD for apical meristem specific expression, SUC2 for phloem specific expression and 35S for high and constitutive expression [3]. These genotypes and the corresponding controls (indicated on the abscissa) were grown under LD at 23°C and flowering recorded as in Fig. 1A. Bars represent the mean ± SEM of at least 12 plants for each genotype.
Mentions: To evaluate which flowering pathways are affected by the gis5 mutation, we investigated the epistatic relationships between gis5 and those mutations affecting the photoperiod, autonomous and vernalization pathways (Fig. 4A-B).

Bottom Line: Here we identify such a mutant which is also thermosensitive.Surprisingly, high expression of SEP3 in vascular tissue promoted FLOWERING LOCUS T (FT) expression, forming a positive feedback loop with SEP3 and leading to early flowering and curly leaves phenotypes.These results strongly suggest that the DNA polymerase δ is required for the proper establishment of transcriptionally active epigenetic marks and that its failure might affect development by affecting the epigenetic control of master genes.

View Article: PubMed Central - PubMed

Affiliation: Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.

ABSTRACT
DNA replication is a key process in living organisms. DNA polymerase α (Polα) initiates strand synthesis, which is performed by Polε and Polδ in leading and lagging strands, respectively. Whereas loss of DNA polymerase activity is incompatible with life, viable mutants of Polα and Polε were isolated, allowing the identification of their functions beyond DNA replication. In contrast, no viable mutants in the Polδ polymerase-domain were reported in multicellular organisms. Here we identify such a mutant which is also thermosensitive. Mutant plants were unable to complete development at 28°C, looked normal at 18°C, but displayed increased expression of DNA replication-stress marker genes, homologous recombination and lysine 4 histone 3 trimethylation at the SEPALLATA3 (SEP3) locus at 24°C, which correlated with ectopic expression of SEP3. Surprisingly, high expression of SEP3 in vascular tissue promoted FLOWERING LOCUS T (FT) expression, forming a positive feedback loop with SEP3 and leading to early flowering and curly leaves phenotypes. These results strongly suggest that the DNA polymerase δ is required for the proper establishment of transcriptionally active epigenetic marks and that its failure might affect development by affecting the epigenetic control of master genes.

Show MeSH
Related in: MedlinePlus