scholarly journals The SAGA complex, together with transcription factors and the endocytic protein Rvs167p, coordinates the reprofiling of gene expression in response to changes in sterol composition inSaccharomyces cerevisiae

2017 ◽  
Vol 28 (20) ◽  
pp. 2637-2649 ◽  
Author(s):  
Gisèle Dewhurst-Maridor ◽  
Daniel Abegg ◽  
Fabrice P. A. David ◽  
Jacques Rougemont ◽  
Cameron C. Scott ◽  
...  

Changes in cellular sterol species and concentrations can have profound effects on the transcriptional profile. In yeast, mutants defective in sterol biosynthesis show a wide range of changes in transcription, including a coinduction of anaerobic genes and ergosterol biosynthesis genes, biosynthesis of basic amino acids, and several stress genes. However the mechanisms underlying these changes are unknown. We identified mutations in the SAGA complex, a coactivator of transcription, which abrogate the ability to carry out most of these sterol-dependent transcriptional changes. In the erg3 mutant, the SAGA complex increases its occupancy time on many of the induced ergosterol and anaerobic gene promoters, increases its association with several relevant transcription factors and the SWI/SNF chromatin remodeling complex, and surprisingly, associates with an endocytic protein, Rvs167p, suggesting a moonlighting function for this protein in the sterol-regulated induction of the heat shock protein, HSP42 and HSP102, mRNAs.

2018 ◽  
Vol 115 (25) ◽  
pp. 6482-6487 ◽  
Author(s):  
Hui Shi ◽  
Mohan Lyu ◽  
Yiwen Luo ◽  
Shoucheng Liu ◽  
Yue Li ◽  
...  

Three families of transcription factors have been reported to play key roles in light control of Arabidopsis seedling morphogenesis. Among them, bHLH protein PIFs and plant-specific protein EIN3/EIN3-LIKE 1 (EIN3/EIL1) accumulate in the dark to maintain skotomorphogenesis. On the other hand, HY5 and HY5 HOMOLOG (HYH), two related bZIP proteins, are stabilized in light and promote photomorphogenic development. To systemically investigate the transcriptional regulation of light-controlled seedling morphogenesis, we generated HY5ox/pifQein3eil1, which contained mutations of EIN3/EIL1 and four PIF genes (pifQein3eil1) and overexpression of HY5. Our results show that dark-grown HY5ox/pifQein3eil1 seedlings display a photomorphogenesis highly similar to that of wild-type seedlings grown in continuous light, with remarkably enhanced photomorphogenic phenotypes compared with the pifQ mutants. Consistent with the genetic evidence, transcriptome analysis indicated that PIFs, EIN3/EIL1, and HY5 are dominant transcription factors in collectively mediating a wide range of light-caused genome-wide transcriptional changes. Moreover, PIFs and EIN3/EIL1 independently control the expression of light-regulated genes such as HLS1 to cooperatively regulate apical hook formation, hypocotyl elongation, and cotyledon opening and expansion. This study illustrates a comprehensive regulatory network of transcription activities that correspond to specific morphological aspects in seedling skotomorphogenesis and photomorphogenesis.


2021 ◽  
Vol 22 (2) ◽  
pp. 522
Author(s):  
Noreen Falak ◽  
Qari Muhammad Imran ◽  
Adil Hussain ◽  
Byung-Wook Yun

Plants are in continuous conflict with the environmental constraints and their sessile nature demands a fine-tuned, well-designed defense mechanism that can cope with a multitude of biotic and abiotic assaults. Therefore, plants have developed innate immunity, R-gene-mediated resistance, and systemic acquired resistance to ensure their survival. Transcription factors (TFs) are among the most important genetic components for the regulation of gene expression and several other biological processes. They bind to specific sequences in the DNA called transcription factor binding sites (TFBSs) that are present in the regulatory regions of genes. Depending on the environmental conditions, TFs can either enhance or suppress transcriptional processes. In the last couple of decades, nitric oxide (NO) emerged as a crucial molecule for signaling and regulating biological processes. Here, we have overviewed the plant defense system, the role of TFs in mediating the defense response, and that how NO can manipulate transcriptional changes including direct post-translational modifications of TFs. We also propose that NO might regulate gene expression by regulating the recruitment of RNA polymerase during transcription.


2006 ◽  
Vol 17 (7) ◽  
pp. 3009-3020 ◽  
Author(s):  
Johan-Owen De Craene ◽  
Jeff Coleman ◽  
Paula Estrada de Martin ◽  
Marc Pypaert ◽  
Scott Anderson ◽  
...  

The endoplasmic reticulum (ER) contains both cisternal and reticular elements in one contiguous structure. We identified rtn1Δ in a systematic screen for yeast mutants with altered ER morphology. The ER in rtn1Δ cells is predominantly cisternal rather than reticular, yet the net surface area of ER is not significantly changed. Rtn1-green fluorescent protein (GFP) associates with the reticular ER at the cell cortex and with the tubules that connect the cortical ER to the nuclear envelope, but not with the nuclear envelope itself. Rtn1p overexpression also results in an altered ER structure. Rtn proteins are found on the ER in a wide range of eukaryotes and are defined by two membrane-spanning domains flanking a conserved hydrophilic loop. Our results suggest that Rtn proteins may direct the formation of reticulated ER. We independently identified Rtn1p in a proteomic screen for proteins associated with the exocyst vesicle tethering complex. The conserved hydophilic loop of Rtn1p binds to the exocyst subunit Sec6p. Overexpression of this loop results in a modest accumulation of secretory vesicles, suggesting impaired exocyst function. The interaction of Rtn1p with the exocyst at the bud tip may trigger the formation of a cortical ER network in yeast buds.


Author(s):  
Derek H. R. Barton ◽  
A. A. Leslie Gunatilaka ◽  
Trevor R. Jarman ◽  
David A. Widdowson ◽  
Martin Bard ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Karen A. Hudson ◽  
Matthew E. Hudson

The complete genome sequence of soybean allows an unprecedented opportunity for the discovery of the genes controlling important traits. In particular, the potential functions of regulatory genes are a priority for analysis. The basic helix-loop-helix (bHLH) family of transcription factors is known to be involved in controlling a wide range of systems critical for crop adaptation and quality, including photosynthesis, light signalling, pigment biosynthesis, and seed pod development. Using a hidden Markov model search algorithm, 319 genes with basic helix-loop-helix transcription factor domains were identified within the soybean genome sequence. These were classified with respect to their predicted DNA binding potential, intron/exon structure, and the phylogeny of the bHLH domain. Evidence is presented that the vast majority (281) of these 319 soybean bHLH genes are expressed at the mRNA level. Of these soybean bHLH genes, 67% were found to exist in two or more homeologous copies. This dataset provides a framework for future studies on bHLH gene function in soybean. The challenge for future research remains to define functions for the bHLH factors encoded in the soybean genome, which may allow greater flexibility for genetic selection of growth and environmental adaptation in this widely grown crop.


2021 ◽  
Author(s):  
Qian-Qian Sha ◽  
Ye-Zhang Zhu ◽  
Yunlong Xiang ◽  
Jia-Li Yu ◽  
Xiao-Ying Fan ◽  
...  

Abstract During oogenesis, oocytes gain competence and subsequently undergo meiotic maturation and prepare for embryonic development; trimethylated histone H3 on lysine-4 (H3K4me3) mediates a wide range of nuclear events during these processes. Oocyte-specific knockout of CxxC-finger protein 1 (CXXC1, also known as CFP1) impairs H3K4me3 accumulation and causes changes in chromatin configurations. This study investigated the changes in genomic H3K4me3 landscapes in oocytes with Cxxc1 knockout and the effects on other epigenetic factors such as the DNA methylation, H3K27me3, H2AK119ub1 and H3K36me3. H3K4me3 is overall decreased after knocking out Cxxc1, including both the promoter region and the gene body. CXXC1 and MLL2, which is another histone H3 methyltransferase, have nonoverlapping roles in mediating H3K4 trimethylation during oogenesis. Cxxc1 deletion caused a decrease in DNA methylation levels and affected H3K27me3 and H2AK119ub1 distributions, particularly at regions with high DNA methylation levels. The changes in epigenetic networks implicated by Cxxc1 deletion were correlated with the transcriptional changes in genes in the corresponding genomic regions. This study elucidates the epigenetic changes underlying the phenotypes and molecular defects in oocytes with deleted Cxxc1 and highlights the role of CXXC1 in orchestrating multiple factors that are involved in establishing the appropriate epigenetic states of maternal genome.


Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 15 ◽  
Author(s):  
He Su ◽  
Yang Chu ◽  
Junqi Bai ◽  
Lu Gong ◽  
Juan Huang ◽  
...  

Herb genomics and comparative genomics provide a global platform to explore the genetics and biology of herbs at the genome level. Panax ginseng C.A. Meyer is an important medicinal plant for a variety of bioactive chemical compounds of which the biosynthesis may involve transport of a wide range of substrates mediated by oligopeptide transporters (OPT). However, information about the OPT family in the plant kingdom is still limited. Only 17 and 18 OPT genes have been characterized for Oryza sativa and Arabidopsis thaliana, respectively. Additionally, few comprehensive studies incorporating the phylogeny, gene structure, paralogs evolution, expression profiling, and co-expression network between transcription factors and OPT genes have been reported for ginseng and other species. In the present study, we performed those analyses comprehensively with both online tools and standalone tools. As a result, we identified a total of 268 non-redundant OPT genes from 12 flowering plants of which 37 were from ginseng. These OPT genes were clustered into two distinct clades in which clade-specific motif compositions were considerably conservative. The distribution of OPT paralogs was indicative of segmental duplication and subsequent structural variation. Expression patterns based on two sources of RNA-Sequence datasets suggested that some OPT genes were expressed in both an organ-specific and tissue-specific manner and might be involved in the functional development of plants. Further co-expression analysis of OPT genes and transcription factors indicated 141 positive and 11 negative links, which shows potent regulators for OPT genes. Overall, the data obtained from our study contribute to a better understanding of the complexity of the OPT gene family in ginseng and other flowering plants. This genetic resource will help improve the interpretation on mechanisms of metabolism transportation and signal transduction during plant development for Panax ginseng.


1996 ◽  
Vol 317 (2) ◽  
pp. 419-423 ◽  
Author(s):  
Nathaniel G. N. MILTON ◽  
Alain BESSIS ◽  
Jean-Pierre CHANGEUX ◽  
David S. LATCHMAN

The regulatory region of the neuronal nicotinic acetylcholine (nACh) receptor α2 subunit gene is activated by the Brn-3b POU family transcription factor but not by the closely related factors Brn-3a and Brn-3c. This pattern of regulation has not previously been observed for other neuronally expressed genes, several of which, such as those encoding α-internexin or SNAP-25, are activated by Brn-3a and Brn-3c but repressed by Brn-3b. The α3 nACh receptor subunit gene is also shown to be activated by Brn-3a but is repressed by Brn-3b and Brn-3c. In contrast, the Brn-3 POU family transcription factors have no effects on either the α7 or β4 nACh receptor subunit genes. The actions of Brn-3b on the α2 subunit are thus in contrast to the inhibitory actions of Brn-3b on several promoters that are activated by Brn-3a. The different actions of the Brn-3 POU factors on the range of nACh receptor genes tested suggests that the novel stimulation of the α2 subunit by Brn-3b is specific to this subunit and not a general feature of nACh receptor genes.


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