scholarly journals The commitment of barley microspores into embryogenesis involves miRNA-directed regulation of members of the SPL, GRF and HD-ZIPIII transcription factor families

2020 ◽  
Author(s):  
Sébastien Bélanger ◽  
Patricia Baldrich ◽  
Marc-André Lemay ◽  
Suzanne Marchand ◽  
Patricio Esteves ◽  
...  

SUMMARYMicrospore embryogenesis is a model for developmental plasticity and cell fate decisions. To investigate the role of miRNAs in this development, we sequenced sRNAs and the degradome of barley microspores collected prior to (day 0) and after (days 2 and 5) the application of a stress treatment known to induce embryogenesis. Microspores isolated at these timepoints were uniform in both appearance and in their complements of sRNAs. We detected 68 miRNAs in microspores. The abundance of 51 of these miRNAs differed significantly during microspore development. One group of miRNAs was induced when the stress treatment was applied, prior to being repressed when microspores transitioned to embryogenesis. Another group of miRNAs were up-regulated in day-2 microspores and their abundance remained stable or increased in day-5 microspores, a timepoint at which the first clear indications of the transition towards embryogenesis were visible. Collectively, these miRNAs might play a role in the modulation of the stress response, the repression of gametic development, and/or the gain of embryogenic potential. A degradome analysis allowed us to validate the role of miRNAs in regulating 41 specific transcripts. We showed that the transition of microspores toward the embryogenesis pathway involves miRNA-directed regulation of members of the ARF, SPL, GRF and HD-ZIPIII transcription factor families. We noted that 41.5% of these targets were shared between day-2 and day-5 microspores while 26.8% were unique to day-5 microspores. The former set may act to disrupt transcripts involved in pollen development while the latter set may drive the commitment to embryogenesis.

2005 ◽  
Vol 14 (2) ◽  
pp. 140-152 ◽  
Author(s):  
Gurudutta U. Gangenahalli ◽  
Pallavi Gupta ◽  
Daman Saluja ◽  
Yogesh K. Verma ◽  
Vimal Kishore ◽  
...  

2020 ◽  
Vol 71 (20) ◽  
pp. 6366-6378 ◽  
Author(s):  
Miyuki Nakamura ◽  
Rita A Batista ◽  
Claudia Köhler ◽  
Lars Hennig

Abstract Epigenetic reprogramming during germ cell formation is essential to gain pluripotency and thus embryogenic potential. The histone modification H3K27me3, which is catalysed by the Polycomb repressive complex 2 (PRC2), regulates important developmental processes in both plants and animals, and defects in PRC2 components cause pleiotropic developmental abnormalities. Nevertheless, the role of H3K27me3 in determining embryogenic potential in gymnosperms is still elusive. To address this, we generated H3K27me3 profiles of Norway spruce (Picea abies) embryonic callus and non-embryogenic callus using CUT&RUN, which is a powerful method for chromatin profiling. Here, we show that H3K27me3 mainly accumulated in genic regions in the Norway spruce genome, similarly to what is observed in other plant species. Interestingly, H3K27me3 levels in embryonic callus were much lower than those in the other examined tissues, but markedly increased upon embryo induction. These results show that H3K27me3 levels are associated with the embryogenic potential of a given tissue, and that the early phase of somatic embryogenesis is accompanied by changes in H3K27me3 levels. Thus, our study provides novel insights into the role of this epigenetic mark in spruce embryogenesis and reinforces the importance of PRC2 as a key regulator of cell fate determination across different plant species.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. SCI-14-SCI-14
Author(s):  
Pier Paolo Pandolfi

Abstract Abstract SCI-14 LRF (Leukemia/lymphoma-related factor, also known as POKEMON) is a member of the POZ and Kruppel (POK) family of transcription factors. LRF has been shown to play an essential role in embryonic development and to act as a master regulator of cellular differentiation in virtually any tissue where it is found expressed, including the hemopoietic compartment. As we will discuss, LRF inactivation in the mouse blocks cellular differentiation in both myeloid/erythroid and lymphoid compartments. On the other hand, LRF has been shown to possess a potent proto-oncogenic activity both in vitro and in vivo. In fact, LRF itself can transform primary cells in combination with known oncogenes and is also essential for cellular transformation of mouse embryonic fibroblasts. In addition, overexpression of LRF in immature B and T progenitor cells in vivo in the mouse lead to lethal precursor T-cell lymphoblastic lymphoma/leukemia. In agreement with this notion, LRF is aberrantly expressed in a variety of human cancers, including diffuse large B cell and follicular lymphomas, but also ovarian and breast cancers. Further, the LRF gene is found amplified in a subset of non-small cell lung cancers (NSCLCs), illustrating a direct role in human cancer. However, we speculated that due to the key role of LRF in cell fate decisions, LRF/POKEMON loss could also contribute to tumorigenesis by blocking cellular differentiation. We will discuss provocative in vivo data in support of the notion that LRF/POKEMON can indeed act as a bona fide tumor suppressor representing a compelling example of two-faced cancer genes. Disclosures: No relevant conflicts of interest to declare.


2015 ◽  
Vol 309 (8) ◽  
pp. C511-C521 ◽  
Author(s):  
Laura Novellasdemunt ◽  
Pedro Antas ◽  
Vivian S. W. Li

The evolutionarily conserved Wnt signaling pathway plays essential roles during embryonic development and tissue homeostasis. Notably, comprehensive genetic studies in Drosophila and mice in the past decades have demonstrated the crucial role of Wnt signaling in intestinal stem cell maintenance by regulating proliferation, differentiation, and cell-fate decisions. Wnt signaling has also been implicated in a variety of cancers and other diseases. Loss of the Wnt pathway negative regulator adenomatous polyposis coli (APC) is the hallmark of human colorectal cancers (CRC). Recent advances in high-throughput sequencing further reveal many novel recurrent Wnt pathway mutations in addition to the well-characterized APC and β-catenin mutations in CRC. Despite attractive strategies to develop drugs for Wnt signaling, major hurdles in therapeutic intervention of the pathway persist. Here we discuss the Wnt-activating mechanisms in CRC and review the current advances and challenges in drug discovery.


2016 ◽  
Vol 311 (4) ◽  
pp. G667-G674 ◽  
Author(s):  
Natalie J. Torok

Reactive oxygen species are implicated in physiological signaling and cell fate decisions. In chronic liver diseases persistent and increased production of oxidative radicals drives a fibrogenic response that is a common feature of disease progression. Despite our understanding the biology of the main prooxidant enzymes, their targets, and antioxidant mechanisms in the liver, there is still lack of knowledge concerning their precise role in the pathogenesis of fibrosis. This review will examine the role of physiological redox signaling in the liver, provide an overview on recent advances in prooxidant and antioxidant pathways that are dysregulated during fibrosis, and highlight possible novel treatment targets.


2018 ◽  
Author(s):  
Zhen Zhang ◽  
Matt P. Parker ◽  
Stefan Graw ◽  
Lesya V. Novikova ◽  
Halyna Fedosyuk ◽  
...  

AbstractThe addition of O-GlcNAc (a single β-D-N-acetylglucosamine sugar at serine and threonine residues) by O-GlcNAc transferase (OGT) and removal by O-GlcNAcase (OGA) maintains homeostatic levels of O-GlcNAc. We investigated the role of O-GlcNAc homeostasis in hematopoiesis utilizing G1E-ER4 cells carrying a GATA-1 transcription factor fused to the estrogen receptor (GATA-1ER) that undergo erythropoiesis following the addition of β-estradiol (E2) and myeloid leukemia cells that differentiate into neutrophils in the presence of all-trans retinoic acid. During G1E-ER4 differentiation, a decrease in overall O-GlcNAc levels and an increase in GATA-1 interactions with OGT and OGA were observed. Transcriptome analysis on G1E-ER4 cells differentiated in the presence of Thiamet-G (TMG), an OGA inhibitor, identified expression changes in 433 GATA-1 target genes. Chromatin immunoprecipitation demonstrated that the occupancy of GATA-1, OGT, and OGA atLaptm5gene GATA site was decreased with TMG. Myeloid leukemia cells showed a decline in O-GlcNAc levels during differentiation and TMG reduced the expression of genes involved in differentiation. Sustained treatment with TMG in G1E-ER4 cells prior to differentiation caused a reduction of hemoglobin positive cells during differentiation. Our results show that alterations in O-GlcNAc homeostasis disrupt transcriptional programs causing differentiation errors suggesting a vital role of O-GlcNAcylation in control of cell fate.


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