Histone modifications at the grapevine VvOMT3 locus, which encodes an enzyme responsible for methoxypyrazine production in the berry

2017 ◽  
Vol 44 (7) ◽  
pp. 655 ◽  
Author(s):  
Juri Battilana ◽  
Jake D. Dunlevy ◽  
Paul K. Boss

Some herbaceous characters in wine are attributed to the presence of aroma compounds collectively known as methoxypyrazines (MPs). In grape berries their formation has been hypothesised to start from a reaction of two amino acids or an amino acid and an unknown 1,2-dicarbonyl compound, leading to the formation of hydroxypyrazine, which is then enzymatically methylated to form a MP. The enzyme responsible of the formation of 3-isobutyl-2-methoxypyrazine has been recently identified as VvOMT3 whose regulation is still not understood. The concentration of MPs in grapes is known to be influenced by development, environmental stimuli and most importantly grape variety. In order to investigate the chromatin arrangement of that region a chromatin immunoprecipitation analysis has been performed and putative differences in epigenetic regulation of VvOMT3 spatially between the skin and flesh tissues and also temporally during fruit development have been detected. There are also allelic differences in VvOMT3 histone modifications which are maintained in subsequent generations. This study provides evidence of histone tail modification of the VvOMT3 locus in grapevine, which may play a role in the spatial and developmental regulation of the expression of this gene.

Genetics ◽  
2019 ◽  
Vol 212 (3) ◽  
pp. 729-742 ◽  
Author(s):  
Lena Annika Street ◽  
Ana Karina Morao ◽  
Lara Heermans Winterkorn ◽  
Chen-Yu Jiao ◽  
Sarah Elizabeth Albritton ◽  
...  

Condensins are evolutionarily conserved protein complexes that are required for chromosome segregation during cell division and genome organization during interphase. In Caenorhabditis elegans, a specialized condensin, which forms the core of the dosage compensation complex (DCC), binds to and represses X chromosome transcription. Here, we analyzed DCC localization and the effect of DCC depletion on histone modifications, transcription factor binding, and gene expression using chromatin immunoprecipitation sequencing and mRNA sequencing. Across the X, the DCC accumulates at accessible gene regulatory sites in active chromatin and not heterochromatin. The DCC is required for reducing the levels of activating histone modifications, including H3K4me3 and H3K27ac, but not repressive modification H3K9me3. In X-to-autosome fusion chromosomes, DCC spreading into the autosomal sequences locally reduces gene expression, thus establishing a direct link between DCC binding and repression. Together, our results indicate that DCC-mediated transcription repression is associated with a reduction in the activity of X chromosomal gene regulatory elements.


2021 ◽  
Vol 12 ◽  
Author(s):  
Weizhi Ouyang ◽  
Xiwen Zhang ◽  
Yong Peng ◽  
Qing Zhang ◽  
Zhilin Cao ◽  
...  

Characterizing genome-wide histone posttranscriptional modifications and transcriptional factor occupancy is crucial for deciphering their biological functions. Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is a powerful method for genome-wide profiling of histone modifications and transcriptional factor-binding sites. However, the current ChIP-seq experimental procedure in plants requires significant material and several days for completion. CUT&Tag is an alternative method of ChIP-seq for low-sample and single-cell epigenomic profiling using protein A-Tn5 transposase fusion proteins (PAT). In this study, we developed a nucleus CUT&Tag (nCUT&Tag) protocol based on the live-cell CUT&Tag technology. Our results indicate that nCUT&Tag could be used for histone modifications profiling in both monocot rice and dicot rapeseed using crosslinked or fresh tissues. In addition, both active and repressive histone marks such as H3K4me3 and H3K9me2 can be identified using our nCUT&Tag. More importantly, all the steps in nCUT&Tag can be finished in only 1 day, and the assay can be performed with as little as 0.01 g of plant tissue as starting materials. Therefore, our results demonstrate that nCUT&Tag is an efficient alternative strategy for plant epigenomic studies.


2020 ◽  
Vol 47 (12) ◽  
pp. 9499-9509
Author(s):  
Buddhini Ranawaka ◽  
Milos Tanurdzic ◽  
Peter Waterhouse ◽  
Fatima Naim

AbstractAll flowering plants have evolved through multiple rounds of polyploidy throughout the evolutionary process. Intergenomic interactions between subgenomes in polyploid plants are predicted to induce chromatin modifications such as histone modifications to regulate expression of gene homoeologs. Nicotiana benthamiana is an ancient allotetraploid plant with ecotypes collected from climatically diverse regions of Australia. Studying the chromatin landscape of this unique collection will likely shed light on the importance of chromatin modifications in gene regulation in polyploids as well its implications in adaptation of plants in environmentally diverse conditions. Generally, chromatin immunoprecipitation and high throughput DNA sequencing (ChIP-seq) is used to study chromatin modifications. However, due to the starchy nature of mature N. benthamiana leaves, previously published protocols were unsuitable. The higher amounts of starch in leaves that co-precipitated with nuclei hindered downstream processing of DNA. Here we present an optimised ChIP protocol for N. benthamiana leaves to facilitate comparison of chromatin modifications in two closely related ecotypes. Several steps of ChIP were optimised including tissue harvesting, nuclei isolation, nuclei storage, DNA shearing and DNA recovery. Commonly available antibodies targeting histone 3 lysine 4 trimethylation (H3K4me3) and histone 3 lysine 9 dimethylation (H3K9me2) histone modifications were used and success of ChIP was confirmed by PCR and next generation sequencing. Collectively, our optimised method is the first comprehensive ChIP method for mature starchy leaves of N. benthamiana to enable studies of chromatin landscape at the genome-wide scale.


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