scholarly journals Molecular Mechanisms Driving Switch Behavior in Xylem Cell Differentiation

Cell Reports ◽  
2019 ◽  
Vol 28 (2) ◽  
pp. 342-351.e4 ◽  
Author(s):  
Gina M. Turco ◽  
Joel Rodriguez-Medina ◽  
Stefan Siebert ◽  
Diane Han ◽  
Miguel Á. Valderrama-Gómez ◽  
...  
2019 ◽  
Author(s):  
Gina M Turco ◽  
Joel Rodriguez-Medina ◽  
Stefan Siebert ◽  
Diane Han ◽  
Hannah Vahldick ◽  
...  

SummaryPlant xylem cells conduct water and mineral nutrients. Although most plant cells are totipotent, xylem cells are unusual and undergo terminal differentiation. Many genes regulating this process are well characterized, including the VASCULAR-RELATED NAC DOMAIN7 (VND7), MYB46 and MYB83 transcription factors which are proposed to act in interconnected feed-forward loops. Much less is known regarding the dynamic behavior underlying the terminal transition to xylem cell differentiation. Here we utilize whole root and single cell data to mathematically model this relationship. These provide evidence for VND7 regulating bistable switching of cells in the root to a xylem cell identity, with additional features of hysteresis. We further determine that although MYB46 responds to VND7 induction, it is not inherently involved in executing the binary switch. A novel regulatory architecture is proposed that involves four downstream targets of VND7 that act in a cycle. These data provide an important model to study the emergent properties that may give rise to totipotency relative to terminal differentiation and reveal novel xylem cell subtypes.


2021 ◽  
Author(s):  
Yudi Gao ◽  
Ke Li ◽  
Yahong Yin ◽  
Yongqiang Li ◽  
Yu Zong ◽  
...  

Abstract Background: Blueberry (Vaccinium corymbosum L.) is one of the most important commercial fruit tree species. The development of high-quality seedlings is a prerequisite for fruit production. Stem cutting and tissue culture methods are widely applied for propagating blueberry seedlings. Both methods require adventitious roots (ARs), indicating ARs are critical for vegetative propagation. However, the underlying factors and molecular mechanisms regulating blueberry AR formation remain relatively unknown. Results: In this study, the rooting abilities of differentially lignified cuttings from various cultivars or the same cultivars cultured differently were evaluated following an indole-3-butyric acid (IBA) treatment. Field-grown semi-lignified and tissue culture-grown cuttings formed ARs, but the latter had more pericycle and secondary xylem cells and formed ARs more easily and faster. WUSCHEL-related homeobox genes are commonly involved in vascular tissue development and early root meristem maintenance. On the basis of the available Vaccinium corymbosum genome data, 29 putative WOX genes with conserved homeodomains were identified and divided into three major clades (modern/WUS, intermediate, and ancient). These 29 WOX genes were differentially expressed in the root, shoot, leaf, flower bud, and fruit. Additionally, a qRT-PCR analysis revealed that five selected VcWOX genes were responsive to an IBA treatment during AR formation. Accordingly, VcWOX4b was functionally characterized. The overexpression of VcWOX4b in transgenic tobacco inhibited AR formation by altering vascular cell division and differentiation and the indole-3-acetic acid (IAA):cytokinin (CTK) ratio. These observations suggest that VcWOX4b regulates the IAA:CTK ratio to promote primary xylem cell differentiation, thereby inhibiting AR formation. However, an IBA treatment can induce AR formation by inhibiting VcWOX4b expression. Conclusions: Current study elucidates the rooting abilities of various cultivars and the cytological characters of influence on AR formation of blueberry cuttings, which may provide novel insights into the selection of high-quality blueberry cuttings. VcWOX4b, VcWOX8/9a, VcWOX11/12c, and VcWOX13b might regulate blueberry AR formation in an IBA-dependent manner. Ectopic expression of VcWOX4b modulated the IAA:CTK ratio to promotes primary xylem cell differentiation, but inhibit secondary xylem cell differentiation, ultimately leading to decreased AR formation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aisajan Mamat ◽  
Kuerban Tusong ◽  
Juan Xu ◽  
Peng Yan ◽  
Chuang Mei ◽  
...  

AbstractKorla pear (Pyrus sinkiangensis Yü) is a landrace selected from a hybrid pear species in the Xinjiang Autonomous Region in China. In recent years, pericarp roughening has been one of the major factors that adversely affects fruit quality. Compared with regular fruits, rough-skin fruits have a greater stone cell content. Stone cells compose sclerenchyma tissue that is formed by secondary thickening of parenchyma cell walls. In this work, we determined the main components of stone cells by isolating them from the pulp of rough-skin fruits at the ripening stage. Stone cell staining and apoptosis detection were then performed on fruit samples that were collected at three different developmental stages (20, 50 and 80 days after flowering (DAF)) representing the prime, late and stationary stages of stone cell differentiation, respectively. The same batches of samples were used for parallel transcriptomic and proteomic analysis to identify candidate genes and proteins that are related to SCW biogenesis in Korla pear fruits. The results showed that stone cells are mainly composed of cellulose (52%), hemicellulose (23%), lignin (20%) and a small amount of polysaccharides (3%). The periods of stone cell differentiation and cell apoptosis were synchronous and primarily occurred from 0 to 50 DAF. The stone cell components increased abundantly at 20 DAF but then decreased gradually. A total of 24,268 differentially expressed genes (DEGs) and 1011 differentially accumulated proteins (DAPs) were identified from the transcriptomic and proteomic data, respectively. We screened the DEGs and DAPs that were enriched in SCW-related pathways, including those associated with lignin biosynthesis (94 DEGs and 31 DAPs), cellulose and xylan biosynthesis (46 DEGs and 18 DAPs), S-adenosylmethionine (SAM) metabolic processes (10 DEGs and 3 DAPs), apoplastic ROS production (16 DEGs and 2 DAPs), and cell death (14 DEGs and 6 DAPs). Among the identified DEGs and DAPs, 63 significantly changed at both the transcript and protein levels during the experimental periods. In addition, the majority of these identified genes and proteins were expressed the most at the prime stage of stone cell differentiation, but their levels gradually decreased at the later stages.


2021 ◽  
Author(s):  
Ankitha Shetty ◽  
Santosh D. Bhosale ◽  
Subhash Kumar Tripathi ◽  
Tanja Buchacher ◽  
Rahul Biradar ◽  
...  

Dysregulated function of Th17 cells has implications in immunodeficiencies and autoimmune disorders. Th17 cell-differentiation is orchestrated by a complex network of transcription factors, including several members of the activator protein (AP-1) family. Among these, FOSL1 and FOSL2 influence the effector responses of Th17 cells. However, the molecular mechanisms underlying their functions are unclear, owing to the poorly characterized protein interaction networks of these factors. Here, we establish the first interactomes of FOSL1 and FOSL2 in human Th17 cells, using affinity purification–mass spectrometry analysis. In addition to the known JUN proteins, we identified several novel binding partners of FOSL1 and FOSL2. Gene ontology analysis found a major fraction of these interactors to be associated with RNA binding activity, which suggests new mechanistic links. Intriguingly, 29 proteins were found to share interactions with FOSL1 and FOSL2, and these included key regulators of Th17-fate. We further validated the binding partners identified in this study by using parallel reaction monitoring targeted mass spectrometry and other methods. Our study provides key insights into the interaction-based signaling mechanisms of FOSL1 and FOSL2 that potentially govern Th17 cell-differentiation and associated pathologies.


Author(s):  
Noriyuki Satoh ◽  
Takuya Deno ◽  
Hiroki Nishida ◽  
Takahito Nishikata ◽  
Kazuhiro W. Makabe

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 674
Author(s):  
Tomoko Yamaguchi ◽  
Yukio Kurihara ◽  
Yuko Makita ◽  
Emiko Okubo-Kurihara ◽  
Ami Kageyama ◽  
...  

Natural rubber is the main component of latex obtained from laticifer cells of Hevea brasiliensis. For improving rubber yield, it is essential to understand the genetic molecular mechanisms responsible for laticifer differentiation and rubber biosynthesis. Jasmonate enhances both secondary laticifer differentiation and rubber biosynthesis. Here, we carried out time-course RNA-seq analysis in suspension-cultured cells treated with methyljasmonic acid (MeJA) to characterize the gene expression profile. Gene Ontology (GO) analysis showed that the term “cell differentiation” was enriched in upregulated genes at 24 h after treatment, but inversely, the term was enriched in downregulated genes at 5 days, indicating that MeJA could induce cell differentiation at an early stage of the response. Jasmonate signaling is activated by MYC2, a basic helix–loop–helix (bHLH)-type transcription factor (TF). The aim of this work was to find any links between transcriptomic changes after MeJA application and regulation by TFs. Using an in vitro binding assay, we traced candidate genes throughout the whole genome that were targeted by four bHLH TFs: Hb_MYC2-1, Hb_MYC2-2, Hb_bHLH1, and Hb_bHLH2. The latter two are highly expressed in laticifer cells. Their physical binding sites were found in the promoter regions of a variety of other TF genes, which are differentially expressed upon MeJA exposure, and rubber biogenesis-related genes including SRPP1 and REF3. These studies suggest the possibilities that Hb_MYC2-1 and Hb_MYC2-2 regulate cell differentiation and that Hb_bHLH1 and Hb_bHLH2 promote rubber biosynthesis. We expect that our findings will help to increase natural rubber yield through genetic control in the future.


Genes ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 21 ◽  
Author(s):  
Ann DeLaForest ◽  
Francesca Di Furio ◽  
Ran Jing ◽  
Amy Ludwig-Kubinski ◽  
Kirk Twaroski ◽  
...  

Elucidating the molecular basis of cell differentiation will advance our understanding of organ development and disease. We have previously established a protocol that efficiently produces cells with hepatocyte characteristics from human induced pluripotent stem cells. We previously used this cell differentiation model to identify the transcription factor hepatocyte nuclear factor 4 α (HNF4A) as being essential during the transition of the endoderm to a hepatic fate. Here, we sought to define the molecular mechanisms through which HNF4A controls this process. By combining HNF4A chromatin immunoprecipitation (ChIP) followed by high-throughput DNA sequencing (ChIP-seq) analyses at the onset of hepatic progenitor cell formation with transcriptome data collected during early stages of differentiation, we identified genes whose expression is directly dependent upon HNF4A. By examining the dynamic changes that occur at the promoters of these HNF4A targets we reveal that HNF4A is essential for recruitment of RNA polymerase (RNA pol) II to genes that are characteristically expressed as the hepatic progenitors differentiate from the endoderm.


2006 ◽  
Vol 18 (2) ◽  
pp. 207
Author(s):  
T. Li ◽  
Y. Xie ◽  
W. Ji

Generating homologous oligodendrocytes are required for studying the molecular mechanisms of oligodendrogliogenesis and for providing donor cells for transplantation therapies. Previous studies have shown that embryonic stem (ES) cells can be induced to generate neural stem cells with many kinds of culture systems; however, few or no oligodendrocytes were obtained from these culture systems. Here we present a simple method containing five steps for obtaining highly enriched oligodendrocyte precursors (75 � 6.8%) and mature oligodendrocytes (81 � 8.6%) from rhesus monkey embryonic stem (rES) cells. We expanded rES cells on a feeder layer of irradiated MESF (ear skin fibroblasts from a one-week-old rhesus monkey), formed embryoid bodies (EBs), promoted Day 9 (3 days in hanging drop and 6 days in suspension) differentiation into highly enriched (90.2 � 6.1%) neural progenitors (NPs) with hepatocyte growth factor (HGF) and G5 supplement [containing 5 ng/mL (bFGF) and 10 ng/mL epidermal growth factor (EGF)], purified NPs with 0.0625% trypsin in 0.04% EDTA (98% of cells were nestin-positive), amplified those progenitors in HGF and G5 media for two months, and then induced oligodendrocyte precursors differentiation in the absence of G5, but in the presence of 20 ng/mL HGF for 2 days. To obtain terminal oligodendrocytes, neurospheres cultured for 2 months were plated on laminin-coated plates for 3 weeks in the presence of HGF. The results showed that differentiated cells expressed myelin basic protein (MBP) and had typical mature oligodendrocyte morphology. Our studies also revealed that HGF significantly increased the NP proliferation speed (P < 0.05) by both decreasing cell apoptosis rate (P < 0.05) and shortening cell cycle time (P < 0.05) in the presence of G5. Additionally, HGF promoted oligodendrocyte maturation by increasing the length and number of branches and the expression of MBP. To test whether the original HGF had similar functions for oligodendrocyte specification, a series of experiments were evaluated by adding HGF or G5 to differentiation or expansion media at different differentiation stages. The results demonstrated that the ability of HGF responsiveness to initiate oligodendrocyte differentiation was regulated by G5 and by HGF alone without G5-induced rES cell differentiation into neurons. Further studies showed that the crucial time point of G5 action was from EBs to NPs; the early addition of HGF to EBs in the presence of G5 increased oligodendrocyte differentiation rate, but was not necessary, and the treatment during the first 2 days was enough to produce a similar effect; and HGF was required for terminal oligodendrocyte differentiation from NPs. Taken together, these results showed that HGF and G5 cooperatively promote rES cell differentiation into highly enriched oligodendrocyte precursors and mature oligodendrocytes.These observations set the method for obtaining highly enriched oligodendrocytes from ES cells in the nonhuman primate for clinical application and provide a platform to probe the molecular mechanisms that control oligodendrocyte differentiation.


2020 ◽  
Vol 11 (9) ◽  
Author(s):  
Jialing Zhang ◽  
Chaoju Hua ◽  
Yu Zhang ◽  
Peng Wei ◽  
Yaping Tu ◽  
...  

Abstract The differentiation of myoblasts plays a key role in the growth of biological individuals and the reconstruction of muscle tissue. Several microRNAs are significantly upregulated during the differentiation of myoblasts and their target genes have been explored. However, the molecular mechanisms underlying the transcriptional regulation of microRNAs remain elusive. In the present study, we found that the expression of miR-133a is increased during the differentiation of C2C12 myoblasts. miR-133a mimic is sufficient to induce the biogenesis of mitochondria and differentiation of C2C12 myoblasts whereas miR-133a inhibitor abolishes cell differentiation. Using CRISPR affinity purification in situ of regulatory elements (CAPTURE) technique, we further dissected the regulatory mechanisms of miR-133a expression and found that KAP1-associated transcription complex accounts for the suppression of miR-133a in C2C12 myoblasts. Knockdown of KAP1 increased the expression of miR-133a, which contributed to the biogenesis of mitochondria and differentiation of C2C12 myoblasts. To our knowledge, this is the first study using the CAPTURE technology to identify the regulatory factors of miR-133a during cell differentiation, which may provide new ideas for understanding the precision regulatory machinery of microRNAs during different biological processes.


2020 ◽  
Vol 217 (9) ◽  
Author(s):  
Agata Cieslak ◽  
Guillaume Charbonnier ◽  
Melania Tesio ◽  
Eve-Lyne Mathieu ◽  
Mohamed Belhocine ◽  
...  

Cell differentiation is accompanied by epigenetic changes leading to precise lineage definition and cell identity. Here we present a comprehensive resource of epigenomic data of human T cell precursors along with an integrative analysis of other hematopoietic populations. Although T cell commitment is accompanied by large scale epigenetic changes, we observed that the majority of distal regulatory elements are constitutively unmethylated throughout T cell differentiation, irrespective of their activation status. Among these, the TCRA gene enhancer (Eα) is in an open and unmethylated chromatin structure well before activation. Integrative analyses revealed that the HOXA5-9 transcription factors repress the Eα enhancer at early stages of T cell differentiation, while their decommission is required for TCRA locus activation and enforced αβ T lineage differentiation. Remarkably, the HOXA-mediated repression of Eα is paralleled by the ectopic expression of homeodomain-related oncogenes in T cell acute lymphoblastic leukemia. These results highlight an analogous enhancer repression mechanism at play in normal and cancer conditions, but imposing distinct developmental constraints.


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