Promoters Of Most Genes Research Articles

Multi-omics provide insights into the regulation of DNA methylation in pear fruit metabolism

BackgroundExtensive research has been conducted on fruit development in crops, but the metabolic regulatory networks underlying perennial fruit trees remain poorly understood. To address this knowledge gap, we conduct a comprehensive analysis of the metabolome, proteome, transcriptome, DNA methylome, and small RNAome profiles of pear fruit flesh at 11 developing stages, spanning from fruitlet to ripening. Here, we systematically investigate the metabolic landscape and regulatory network involved.ResultsWe generate an association database consisting of 439 metabolites and 14,399 genes to elucidate the gene regulatory network of pear flesh metabolism. Interestingly, we detect increased DNA methylation in the promoters of most genes within the database during pear flesh development. Application of a DNA methylation inhibitor to the developing fruit represses chlorophyll degradation in the pericarp and promotes xanthophyll, β-carotene, and abscisic acid (ABA) accumulation in the flesh. We find the gradual increase in ABA production during pear flesh development is correlated with the expression of several carotenoid pathway genes and multiple transcription factors. Of these transcription factors, the zinc finger protein PbZFP1 is identified as a positive mediator of ABA biosynthesis in pear flesh. Most ABA pathway genes and transcription factors are modified by DNA methylation in the promoters, although some are induced by the DNA methylation inhibitor. These results suggest that DNA methylation inhibits ABA accumulation, which may delay fruit ripening.ConclusionOur findings provide insights into epigenetic regulation of metabolic regulatory networks during pear flesh development, particularly with regard to DNA methylation.

Function Analysis of the ERF and DREB Subfamilies in Tomato Fruit Development and Ripening.

APETALA2/ethylene responsive factors (AP2/ERF) are unique regulators in the plant kingdom and are involved in the whole life activity processes such as development, ripening, and biotic and abiotic stresses. In tomato (Solanum lycopersicum), there are 140 AP2/ERF genes; however, their functionality remains poorly understood. In this work, the 14th and 19th amino acid differences in the AP2 domain were used to distinguish DREB and ERF subfamily members. Even when the AP2 domain of 68 ERF proteins from 20 plant species and motifs in tomato DREB and ERF proteins were compared, the binding ability of DREB and ERF proteins with DRE/CRT and/or GCC boxes remained unknown. During fruit development and ripening, the expressions of 13 DREB and 19 ERF subfamily genes showed some regular changes, and the promoters of most genes had ARF, DRE/CRT, and/or GCC boxes. This suggests that these genes directly or indirectly respond to IAA and/or ethylene (ET) signals during fruit development and ripening. Moreover, some of these may feedback regulate IAA or ET biosynthesis. In addition, 16 EAR motif-containing ERF genes in tomato were expressed in many organs and their total transcripts per million (TPM) values exceeded those of other ERF genes in most organs. To determine whether the EAR motif in EAR motif-containing ERF proteins has repression function, their EAR motifs were retained or deleted in a yeast one-hybrid (YIH) assay. The results indicate that most of EAR motif-containing ERF proteins lost repression activity after deleting the EAR motif. Moreover, some of these were expressed during ripening. Thus, these EAR motif-containing ERF proteins play vital roles in balancing the regulatory functions of other ERF proteins by completing the DRE/CRT and/or GCC box sites of target genes to ensure normal growth and development in tomato.

Molecular analysis indicates the involvement of Jasmonic acid biosynthesis pathway in low-potassium (K+) stress response and development in chickpea (Cicer arietinum)

K + is a major macronutrient and its deficiency hampers plant growth and yield. Plants combat low-K + stress by modifying their root system architecture (RSA). Here, morphophysiological analysis revealed that chickpea plants exhibit sensitivity to low-K + stress as shown by impaired primary root growth. Phytohormone JA regulates various facets of plant root growth, however, information of JA biosynthesis genes in chickpea is missing. We performed genome-wide identification and molecular characterization of JA biosynthesis pathway genes in chickpea. Total 33 genes belonging to different families i.e., LOX s-18, AOS s-3, AOC s-2, OPR s-6 and JAR s-4 were identified in the chickpea genome. In-planta analysis revealed the localization of CaLOX7, − 10, CaAOS1, − 2 and CaAOC1 at subcellular compartments, such as membrane, chloroplast and cytoplasm. Protein expression and in-vitro enzymatic activity analysis showed that CaAOS1 an CaOPR2 are the functional enzymes in chickpea. Promoters of most genes harboured abiotic stress, hormone and development related cis -regulatory elements, suggesting their role in nutrient deficiency, abiotic stress and plant development. qRT-PCR expression profiling showed that about 15 JA biosynthesis genes from different families express differentially whereas, JA catabolism genes were repressed in chickpea root and shoot under low-K + stress. In addition, JA biosynthesis genes showed differential expression in vegetative and reproductive development, senescence stages, desiccation, salinity and cold stress. These findings indicate the involvement of JA biosynthesis pathway in low-K + stress response and development in chickpea. Low-K + stress and development related genes identified in this study could be utilized in genetic engineering of chickpea plants for improved traits. • 33 JA biosynthesis pathway genes (18 LOXs, 3 AOSs, 2AOCs, 6 OPRs and 4 JARs) are identified in the chickpea genome. • They were localized at sub-cellular compartments such as, chloroplast, plasma membrane, cytoplasm and nucleus. • Enzymatic activity assay revealed that CaAOS1 and CaOPR2 are the functional enzymes. • Several genes from different families were differentially expressed under K + deficiency in chickpea. • Expression analysis indicate their overlapping function in low-K + stress, abiotic stresses, and plant development.

Exploring the diversity of promoter and 5'UTR sequences in ancestral, historic and modern wheat.

A data set of promoter and 5′UTR sequences of homoeo‐alleles of 459 wheat genes that contribute to agriculturally important traits in 95 ancestral and commercial wheat cultivars is presented here. The high‐stringency myBaits technology used made individual capture of homoeo‐allele promoters possible, which is reported here for the first time. Promoters of most genes are remarkably conserved across the 83 hexaploid cultivars used with <7 haplotypes per promoter and 21% being identical to the reference Chinese Spring. InDels and many high‐confidence SNPs are located within predicted plant transcription factor binding sites, potentially changing gene expression. Most haplotypes found in the Watkins landraces and a few haplotypes found in Triticum monococcum, germplasms hitherto not thought to have been used in modern wheat breeding, are already found in many commercial hexaploid wheats. The full data set which is useful for genomic and gene function studies and wheat breeding is available at https://rrescloud.rothamsted.ac.uk/index.php/s/DMCFDu5iAGTl50u/authenticate.

The stress-regulatory transcription factors Msn2 and Msn4 regulate fatty acid oxidation in budding yeast

The transcription factors Msn2 and Msn4 (multicopy suppressor of SNF1 mutation proteins 2 and 4) bind the stress-response element in gene promoters in the yeast Saccharomyces cerevisiae However, the roles of Msn2/4 in primary metabolic pathways such as fatty acid β-oxidation are unclear. Here, in silico analysis revealed that the promoters of most genes involved in the biogenesis, function, and regulation of the peroxisome contain Msn2/4-binding sites. We also found that transcript levels of MSN2/MSN4 are increased in glucose-depletion conditions and that during growth in nonpreferred carbon sources, Msn2 is constantly localized to the nucleus in wild-type cells. Of note, the double mutant msn2Δmsn4Δ exhibited a severe growth defect when grown with oleic acid as the sole carbon source and had reduced transcript levels of major β-oxidation genes. ChIP indicated that Msn2 has increased occupancy on the promoters of β-oxidation genes in glucose-depleted conditions, and in vivo reporter gene analysis indicated reduced expression of these genes in msn2Δmsn4Δ cells. Moreover, mobility shift assays revealed that Msn4 binds β-oxidation gene promoters. Immunofluorescence microscopy with anti-peroxisome membrane protein antibodies disclosed that the msn2Δmsn4Δ strain had fewer peroxisomes than the wild type, and lipid analysis indicated that the msn2Δmsn4Δ strain had increased triacylglycerol and steryl ester levels. Collectively, our data suggest that Msn2/Msn4 transcription factors activate expression of the genes involved in fatty acid oxidation. Because glucose sensing, signaling, and fatty acid β-oxidation pathways are evolutionarily conserved throughout eukaryotes, the msn2Δmsn4Δ strain could therefore be a good model system for further study of these critical processes.

Genome-Wide Control of RNA Polymerase II Activity by Cohesin

Cohesin is a well-known mediator of sister chromatid cohesion, but it also influences gene expression and development. These non-canonical roles of cohesin are not well understood, but are vital: gene expression and development are altered by modest changes in cohesin function that do not disrupt chromatid cohesion. To clarify cohesin's roles in transcription, we measured how cohesin controls RNA polymerase II (Pol II) activity by genome-wide chromatin immunoprecipitation and precision global run-on sequencing. On average, cohesin-binding genes have more transcriptionally active Pol II and promoter-proximal Pol II pausing than non-binding genes, and are more efficient, producing higher steady state levels of mRNA per transcribing Pol II complex. Cohesin depletion frequently decreases gene body transcription but increases pausing at cohesin-binding genes, indicating that cohesin often facilitates transition of paused Pol II to elongation. In many cases, this likely reflects a role for cohesin in transcriptional enhancer function. Strikingly, more than 95% of predicted extragenic enhancers bind cohesin, and cohesin depletion can reduce their association with Pol II, indicating that cohesin facilitates enhancer-promoter contact. Cohesin depletion decreases the levels of transcriptionally engaged Pol II at the promoters of most genes that don't bind cohesin, suggesting that cohesin controls expression of one or more broadly acting general transcription factors. The multiple transcriptional roles of cohesin revealed by these studies likely underlie the growth and developmental deficits caused by minor changes in cohesin activity.

Variations in the epigenetic regulation of lineage-specific genes among human pluripotent stem cell lines

Pluripotent stem cells (PSCs) have unique transcriptional regulatory networks and epigenetic states that are involved in maintaining pluripotency. In this study, the transcriptional levels and histone modifications of lineage-specific genes were compared for human ESC (hESC) lines and human induced pluripotent stem cell (hiPSC) lines. Expression of the pluripotency marker genes, OCT4, SOX2, and NANOG, was largely modulated in hESCs by permissive histone marks, whereas hiPSC lines showed differential histone modifications in the gene promoters. The permissive histone mark, H3K4me3, predominantly contributed to expression of the oncogene, c-MYC, in hESC lines, whereas histone modifications of the c-MYC promoter varied between hiPSC lines. Interestingly, the transcriptional levels and epigenetic marks in the promoters of the developmental genes such as SOX17, T, and NESTIN varied among individual hiPSC lines. In particular, a partially-reprogrammed hiPSC cell line showed lower frequencies of permissive and repressive histone marks in the promoters of most genes, indicating incomplete epigenetic reprogramming. Our data indicate that respective hPSCs have distinct epigenetic signatures of lineage-specific genes, thereby leading to in their propensities to follow a particular differentiation pathway.

Orphan CpG Islands Identify Numerous Conserved Promoters in the Mammalian Genome

CpG islands (CGIs) are vertebrate genomic landmarks that encompass the promoters of most genes and often lack DNA methylation. Querying their apparent importance, the number of CGIs is reported to vary widely in different species and many do not co-localise with annotated promoters. We set out to quantify the number of CGIs in mouse and human genomes using CXXC Affinity Purification plus deep sequencing (CAP-seq). We also asked whether CGIs not associated with annotated transcripts share properties with those at known promoters. We found that, contrary to previous estimates, CGI abundance in humans and mice is very similar and many are at conserved locations relative to genes. In each species CpG density correlates positively with the degree of H3K4 trimethylation, supporting the hypothesis that these two properties are mechanistically interdependent. Approximately half of mammalian CGIs (>10,000) are “orphans” that are not associated with annotated promoters. Many orphan CGIs show evidence of transcriptional initiation and dynamic expression during development. Unlike CGIs at known promoters, orphan CGIs are frequently subject to DNA methylation during development, and this is accompanied by loss of their active promoter features. In colorectal tumors, however, orphan CGIs are not preferentially methylated, suggesting that cancer does not recapitulate a developmental program. Human and mouse genomes have similar numbers of CGIs, over half of which are remote from known promoters. Orphan CGIs nevertheless have the characteristics of functional promoters, though they are much more likely than promoter CGIs to become methylated during development and hence lose these properties. The data indicate that orphan CGIs correspond to previously undetected promoters whose transcriptional activity may play a functional role during development.

Chz1, a Nuclear Chaperone for Histone H2AZ

The histone variant H2AZ marks nucleosomes flanking the promoters of most genes of budding yeast. The incorporation of H2AZ into chromatin is dependent on the SWR1 complex, which catalyses the replacement of conventional histone H2A with H2AZ. In cells, the pool of unincorporated histone H2AZ has previously been found in association with Nap1, a chaperone for conventional histone H2A-H2B. Here, we report the discovery of Chz1, a histone chaperone that has preference for H2AZ and can also deliver a source of the histone variant for SWR1-dependent histone replacement. Bacterially expressed Chz1 forms a heterotrimer with H2AZ-H2B, stabilizing the association of the histone dimer. We have identified a conserved motif important for histone variant recognition within the H2AZ-interacting domain of Chz1. The presence of this motif in other metazoan proteins suggests that H2AZ-specific chaperones may be widely conserved.

Distinct DNase I hypersensitive sites are absent from promoters of transcriptionally incompetent genes in Arabidopsis

Specifically accessible chromatin sites, detected as DNase I hypersensitive sites (DNase I HSs), have been found at promoters of most genes in yeast, human as well as in Arabidopsis chromatin. The DNase I HSs are constitutively present at promoters of most genes both at inactive and activated states. On the other hand, appearance and disappearance of DNase I HSs have been observed at several developmentally regulated genes in different tissues of animals. Patterns of appearance and disappearance of DNase I HSs were correlated with transcriptional competency (potential of expression) of the associated genes, suggesting that DNase I HSs are absent from the promoters of transcriptionally incompetent (unexpressed nor inducible) genes. To test this hypothesis in plants, we analyzed DNase I hypersensitivity of several well- characterized genes showing distinct patterns of tissue-specific expression in Arabidopsis leaves, roots and suspension cells. Distinct DNase I HSs were present at transcriptionally competent gene promoters, but absent from incompetent gene promoters. The absence of DNase I HS suggests that nucleosomes are randomly positioned on incompetent promoters, and may contribute to the transcriptional incompetency by blocking the binding of activators in tissues where expression of these genes is unnecessary.

Involvement of oxidants and AP-1 in angiotensin II-activated NFAT3 transcription factor

Cardiomyocyte hypertrophy is associated with multiple pathophysiological cardiovascular conditions. Recent studies have substantiated the finding that oxidants may contribute to the development of cardiomyocyte hypertrophy. Activation of the nuclear factor of activated T cells-3 (NFAT3) transcription factor has been shown to result from endocrine inducers of cardiomyocyte hypertrophy such as angiotensin II (ANG II) and serves as an important molecular regulator of cardiomyocyte hypertrophy. In this study, we found that antioxidant enzyme catalase and antioxidants N-acetyl-l-cysteine, alpha-phenyl-N-tert-butylnitrone, and lipoic acid prevent ANG II from activating NFAT3 promoter-luciferase. H(2)O(2) induces a time- and dose-dependent activation of NFAT3 transcription factor. A dominant negative form of NFAT3 transcription factor inhibited H(2)O(2) from activating NFAT3 promoter. An inhibitor of ERKs, but not phosphoinositide 3-kinase or p38 MAPKs, blocked NFAT3 activation by H(2)O(2). The NFAT3 binding site in the promoters of most genes contains a weak activator protein-1 (AP-1) binding site adjacent to the core consensus NFAT binding sequence. ERK inhibitor PD98059 was found previously to inhibit AP-1 activation by H(2)O(2). Inactivation of AP-1 transcription factor by cotransfection of a dominant negative c-Jun, TAM67, prevented H(2)O(2) or ANG II from activating NFAT3 promoter. NFAT3 promoter containing the core NFAT cis-element without AP-1 binding site failed to show activation by H(2)O(2) treatment. Our data suggest that hypertrophy inducers ANG II and H(2)O(2) may activate NFAT3 in cardiomyocyte through an AP-1 transcription factor-dependent mechanism.

Stability and evolution of transcriptional regulatory networks

Stability and evolution of transcriptional regulatory networks