scholarly journals Control of stem cell niche and fruit development in Arabidopsis thaliana by AGO10/ZWL requires the bHLH transcription factor INDEHISCENT

2020 ◽  
Author(s):  
Manoj Valluru ◽  
Karim Sorefan
Keyword(s):  
Transcription Factor ◽  
Embryonic Development ◽  
Pluripotent Stem Cells ◽  
Apical Meristem ◽  
Leucine Zipper ◽  
Bhlh Transcription Factor ◽  
Loss Of Function ◽  
Class Iii ◽  
Auxin Transporter ◽  
Cell Niche

AbstractBackgroundThe shoot apical meristem (SAM) in plants is composed of a small mound of pluripotent stem cells that generate new organs. ARGONAUTE10 (AGO10) is known to be critical for maintenance of the embryonic SAM by regulating the expression of Class III HOMEODOMAIN-LEUCINE ZIPPER (HD-ZIP III) transcription factors, which then modulate downstream responses to the key phytohormone auxin. However, we do not understand how AGO10 modulates auxin responses after embryogenesis in the mature plant.ResultsHere we show that AGO10 regulates auxin responses in the post-embryonic SAM via the bHLH transcription factor INDEHISCENT (IND). IND directly regulates auxin responses in the SAM regulating the auxin transporter PIN1 via direct transcriptional regulation of PINOID kinase. We show that a loss of function ind mutation significantly restores ago10zwl-3 mutant SAM and fruit phenotypes. ago10zwl-3 mutants overexpress IND and overexpression of IND phenocopies the ago10zwl-3 SAM phenotypes, and regulates auxin transport and responses in the SAM. AGO10 also regulates post-embryonic development in the fruit via a similar genetic pathway.ConclusionsWe characterise a molecular mechanism that is conserved during post embryonic development linking AGO10 directly to auxin responses.

scholarly journals Loss of function of bHLH transcription factor Nrd1 in tomato induces an arabinogalactan protein-encoding gene and enhances resistance to Pseudomonas syringae pv. tomato

2021 ◽  
Author(s):  
Ning Zhang ◽  
Chloe Hecht ◽  
Xuepeng Sun ◽  
Zhangjun Fei ◽  
Gregory B Martin
Keyword(s):  
Transcription Factor ◽  
Pseudomonas Syringae ◽  
Transcript Abundance ◽  
Negative Regulator ◽  
Arabinogalactan Protein ◽  
Bhlh Transcription Factor ◽  
Dependent Manner ◽  
Rna Seq ◽  
Loss Of Function ◽  
Encoding Gene

Basic helix-loop-helix (bHLH) transcription factors constitute a superfamily in eukaryotes but their roles in plant immunity remain largely uncharacterized. We found that the transcript abundance in tomato leaves of one bHLH transcription factor-encoding gene, Nrd1 (negative regulator of resistance to DC3000 1), was significantly increased after treatment with the immunity-inducing flgII-28 peptide. Plants carrying a loss-of-function mutation in Nrd1 (Δnrd1) showed enhanced resistance to Pseudomonas syringae pv. tomato (Pst) DC3000 although early pattern-triggered immunity responses such as generation of reactive oxygen species and activation of mitogen-activated protein kinases after treatment with flagellin-derived flg22 and flgII-28 peptides were unaltered compared to wild-type plants. An RNA-Seq analysis identified a gene, Agp1, whose expression is strongly suppressed in an Nrd1-dependent manner. Agp1 encodes an arabinogalactan protein and overexpression of the Agp1 gene in Nicotiana benthamiana led to ~10-fold less Pst growth compared to the control. These results suggest that the Nrd1 protein promotes tomato susceptibility to Pst by suppressing the defense gene Agp1. RNA-Seq also revealed that loss of Nrd1 function has no effect on the transcript abundance of immunity-associated genes including Bti9, Core, Fls2, Fls3 and Wak1 upon Pst inoculation, suggesting that the enhanced immunity observed in the Δnrd1 mutants is due to the activation of key PRR signaling components as well as loss of Nrd1-regulated suppression of Agp1.

The shoot apical meristem and development of vascular architectureThis review is one of a selection of papers published on the Special Theme of Shoot Apical Meristems.

2006 ◽  
Vol 84 (11) ◽  
pp. 1660-1671 ◽  
Author(s):  
Nancy G. Dengler
Keyword(s):  
Arabidopsis Thaliana ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Leucine Zipper ◽  
Vascular Tissue ◽  
Vascular System ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Integrative Model ◽  
Class Iii

The shoot apical meristem (SAM) functions to generate external architecture and internal tissue pattern as well as to maintain a self-perpetuating population of stem-cell-like cells. The internal three-dimensional architecture of the vascular system corresponds closely to the external arrangement of lateral organs, or phyllotaxis. This paper reviews this correspondence for dicotyledonous plants in general and in Arabidopsis thaliana (L.) Heynh., specifically. Analysis is partly based on the expression patterns of the class III homeodomain-leucine zipper transcription factor ARABIDOPSIS THALIANA HOMEOBOX GENE 8 (ATHB8), a marker of the procambial and preprocambial stages of vascular development, and on the anatomical criteria for recognizing vascular tissue pattern. The close correspondence between phyllotaxis and vascular pattern present in mature tissues arises at early stages of development, at least by the first plastochron of leaf primordium outgrowth. Current literature provides an integrative model in which local variation in auxin concentration regulates both primordium formation on the SAM and the first indications of a procambial prepattern in the position of primordium leaf trace as well as in the elaboration of leaf vein pattern. The prospects for extending this model to the development of the complex three-dimensional vascular architecture of the shoot are promising.

Myc protein: function, pathway and mutation

2014 ◽  
Vol 2 (3) ◽  
pp. 147-159
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Protein Function ◽  
Cell Biology ◽  
Leucine Zipper ◽  
Target Genes ◽  
Biological Effects ◽  
Bhlh Transcription Factor ◽  
Direct Role ◽  
Leucine Zipper Domain

Myc protein belongs to Myc family of transcription factors, there are 3 types of Myc: c-Myc, N-Myc, and L-Myc expression by dendritic cells is required for optimal T cell priming. Myc family of transcription factors contain bHLH/LZ (basic Helix-Loop-Helix Leucine Zipper) domain. Through its bHLH domain can bind to DNA, while the leucine zipper domain allows the dimerization with its partner Max, another bHLH transcription factor. Myc protien is a transcription factor that activates expression of many genes through binding on consensus sequences (Enhancer Box sequences (E-boxes)) and recruiting histone acetyltransferase (HATs). The first to be discovered was its capability to drive cell proliferation (upregulates cyclins, downregulates p21), but it also plays a very important role in regulating cell growth (upregulates ribosomal RNA and proteins), apoptosis (downregulates Bcl-2), differentiation, and stem cell self-renewal. Myc is a very strong proto-oncogene and it is very often found to be upregulated in many types of cancers. Myc overexpression stimulates gene amplification, presumably through DNA over-replication. It can also act as a transcriptional repressor. By binding Miz-1 transcription factor and displacing the p300 co-activator, it inhibits expression of Miz-1 target genes. In addition, myc has a direct role in the control of DNA replication. Myc is activated upon various mitogenic signals such as Wnt, Shh and EGF (via the MAPK/ERK pathway). By modifying the expression of its target genes, Myc activation results in numerous biological effects. This paper will provide researchers with a critical appraisal of Myc in cell biology.

scholarly journals FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (OsFIT) interacts with OsIRO2 to regulate iron homeostasis

2020 ◽  
Author(s):  
Gang Liang ◽  
Huimin Zhang ◽  
Yang Li ◽  
Mengna Pu ◽  
Yujie Yang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Oryza Sativa ◽  
Iron Homeostasis ◽  
Transcription Activation ◽  
Fe Deficiency ◽  
Bhlh Transcription Factor ◽  
Loss Of Function ◽  
Deficiency Symptoms ◽  
Fe Uptake ◽  
Fe Homeostasis

ABSTRACTThere are two Fe-uptake strategies for maintaining Fe homeostasis in plants. As a special graminaceous plant, rice applies both strategies. However, it remains unclear how these two strategies are regulated in rice. IRON-RELATED BHLH TRANSCRIPTION FACTOR 2 (OsIRO2) is critical for regulating Fe uptake in rice. In this study, we identified an interacting partner of OsIRO2, Oryza sativa FER-LIKE FE DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (OsFIT), which encodes a bHLH transcription factor. The OsIRO2 protein is localized in the cytoplasm and nucleus, but OsFIT facilitates the accumulation of OsIRO2 in the nucleus. Loss-of-function mutations to OsFIT result in decreased Fe accumulation, severe Fe-deficiency symptoms, and disrupted expression of Fe-uptake genes. In contrast, OsFIT overexpression promotes Fe accumulation and the expression of Fe-uptake genes. Genetic analyses indicated that OsFIT and OsIRO2 function in the same genetic node. Further analysis suggested that OsFIT and OsIRO2 form a functional transcription activation complex to initiate the expression of Fe-uptake genes. Our findings provide a mechanism understanding of how rice maintains Fe homeostasis.One-sentence summaryOsFIT interacts with and facilitates the accumulation of OsIRO2 in the nucleus where the OsFIT-OsIRO2 transcription complex initiates the transcription of Fe deficiency responsive genes.

scholarly journals bHLH Transcription Factor Math6 Antagonizes TGF-β Signalling in Reprogramming, Pluripotency and Early Cell Fate Decisions

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 529 ◽  
Author(s):  
Satya Srirama Karthik Divvela ◽  
Patrick Nell ◽  
Markus Napirei ◽  
Holm Zaehres ◽  
Jiayu Chen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factor ◽  
Cell Fate ◽  
Pluripotent Stem Cells ◽  
Cellular Reprogramming ◽  
Bhlh Transcription Factor ◽  
Tgf Beta ◽  
Cell Fate Decisions ◽  
Helix Loop Helix ◽  
Induced Pluripotent

The basic helix-loop-helix (bHLH) transcription factor Math6 (Atonal homolog 8; Atoh8) plays a crucial role in a number of cellular processes during embryonic development, iron metabolism and tumorigenesis. We report here on its involvement in cellular reprogramming from fibroblasts to induced pluripotent stem cells, in the maintenance of pluripotency and in early fate decisions during murine development. Loss of Math6 disrupts mesenchymal-to-epithelial transition during reprogramming and primes pluripotent stem cells towards the mesendodermal fate. Math6 can thus be considered a regulator of reprogramming and pluripotent stem cell fate. Additionally, our results demonstrate the involvement of Math6 in SMAD-dependent TGF beta signalling. We furthermore monitor the presence of the Math6 protein during these developmental processes using a newly generated Math6Flag-tag mouse. Taken together, our results suggest that Math6 counteracts TGF beta signalling and, by this, affects the initiating step of cellular reprogramming, as well as the maintenance of pluripotency and early differentiation.

scholarly journals The SlHB8 Acts as a Negative Regulator in Stem Development and Lignin Biosynthesis

2021 ◽  
Vol 22 (24) ◽  
pp. 13343
Author(s):  
Xiaojuan Liu ◽  
Caiyu Wu ◽  
Deding Su ◽  
Yang Yang ◽  
Zhiqiang Xian ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Expression Profiles ◽  
Lignin Biosynthesis ◽  
Stem Diameter ◽  
Negative Regulator ◽  
Biosynthesis Pathway ◽  
Loss Of Function ◽  
Class Iii ◽  
Cell Layers ◽  
Stem Development

The stem is an important organ in supporting plant body, transporting nutrients and communicating signals for plant growing. However, studies on the regulation of stem development in tomato are rather limited. In our study, we demonstrated that SlHB8 negatively regulated tomato stem development. SlHB8 belongs to homeo domain-leucine zipper Class III gene family transcription factors and expressed in all the organs examined including root, stem, leaves, flower, and fruit. Among these tissues, SlHB8 showed stable high expression level during tomato stem development. Overexpression of SlHB8 gene decreased stem diameter with inhibited xylem width and xylem cell layers, while loss of function of SlHB8gene increased the stem diameter and xylem width. The contents of lignin were decreased both in leaves and stems of SlHB8 overexpression plants. RNA-seq analysis on the stems of wild type and SlHB8 transgenic plants showed that the 116 DEGs (differential expressed genes) with reversible expression profiles in SlHB8-ox and SlHB8-cr plants were significantly enriched in the phenylpropanoid biosynthesis pathway and plant-pathogen pathway which were related to lignin biosynthesis and disease resistance. Meanwhile, the key genes involved in the lignin biosynthesis pathway such as SlCCR (cinnamoyl-CoA reductase), SlCYP73A14/C4H (cinnamate 4-hydroxylase), SlC3H (coumarate 3-hydroxylase) and SlCAD (cinnamoyl alcohol dehydrogenase) were down-regulated in both stem and leaves of SlHB8 overexpression plants, indicating a negative regulatory role of SlHB8 in the lignin biosynthesis and stem development.

Sign in / Sign up

Export Citation Format

Share Document