Plant adjustment to environmental changes involves complex crosstalk between extrinsic and intrinsic cues. In the past two decades, extensive research has elucidated the key roles of PHYTOCHROME-INTERACTING FACTOR4 (PIF4) and the phytohormone auxin in thermomorphogenesis. In this study, we identified a previously unexplored role of jasmonate (JA) signaling components, the Mediator complex, and their integration with auxin signaling during thermomorphogenesis in Arabidopsis (Arabidopsis thaliana). Warm temperature induces expression of JA signaling genes including MYC2, but, surprisingly, this transcriptional activation is not JA dependent. Warm temperature also promotes accumulation of the JA signaling receptor CORONATINE INSENSITIVE1 (COI1) and degradation of the JA signaling repressor JASMONATE-ZIM-DOMAIN PROTEIN9, which probably leads to de-repression of MYC2, enabling it to contribute to the expression of MEDIATOR SUBUNIT17 (MED17). In response to warm temperature, MED17 occupies the promoters of thermosensory genes including PIF4, YUCCA8 (YUC8), INDOLE-3-ACETIC ACID INDUCIBLE19 (IAA19), and IAA29. Moreover, MED17 facilitates enrichment of H3K4me3 on the promoters of PIF4, YUC8, IAA19, and IAA29 genes. Interestingly, both occupancy of MED17 and enrichment of H3K4me3 on these thermomorphogenesis-related promoters are dependent on PIF4 (or PIFs). Altered accumulation of COI1 under warm temperature in the med17 mutant suggests the possibility of a feedback mechanism. Overall, this study reveals the role of the Mediator complex as an integrator of JA and auxin signaling pathways during thermomorphogenesis.

• MeSH
• Arabidopsis * metabolismus   MeSH
• cyklopentany metabolismus   MeSH
• kyseliny indoloctové metabolismus   MeSH
• mediátorový komplex metabolismus   MeSH
• oxylipiny metabolismus   MeSH
• proteiny huseníčku * metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• signální transdukce MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklopentany MeSH
• jasmonic acid MeSH Prohlížeč
• kyseliny indoloctové MeSH
• mediátorový komplex MeSH
• oxylipiny MeSH
• proteiny huseníčku * MeSH

The mediator (MED) represents a large, conserved, multi-subunit protein complex that regulates gene expression through interactions with RNA polymerase II and enhancer-bound transcription factors. Expanding research accomplishments suggest the predominant role of plant MED subunits in the regulation of various physiological and developmental processes, including the biotic stress response against bacterial and fungal pathogens. However, the involvement of MED subunits in virus/viroid pathogenesis remains elusive. In this study, we investigated for the first time the gene expression modulation of selected MED subunits in response to five viroid species (Apple fruit crinkle viroid (AFCVd), Citrus bark cracking viroid (CBCVd), Hop latent viroid (HLVd), Hop stunt viroid (HSVd), and Potato spindle tuber viroid (PSTVd)) in two model plant species (Nicotiana tabacum and N. benthamiana) and a commercially important hop (Humulus lupulus) cultivar. Our results showed a differential expression pattern of MED subunits in response to a viroid infection. The individual plant MED subunits displayed a differential and tailored expression pattern in response to different viroid species, suggesting that the MED expression is viroid- and plant species-dependent. The explicit evidence obtained from our results warrants further investigation into the association of the MED subunit with symptom development. Together, we provide a comprehensive portrait of MED subunit expression in response to viroid infection and a plausible involvement of MED subunits in fine-tuning transcriptional reprogramming in response to viroid infection, suggesting them as a potential candidate for rewiring the defense response network in plants against pathogens.

• Klíčová slova
• Nicotiana benthamiana, Nicotiana tabacum, differential expression, hop, mediator complex, pathogen, quantitative reverse transcription PCR, viroid,
• MeSH
• druhová specificita MeSH
• Humulus genetika   virologie   MeSH
• listy rostlin genetika   mikrobiologie   MeSH
• mediátorový komplex genetika   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny genetika   MeSH
• rostlinné viry MeSH
• stanovení celkové genové exprese MeSH
• tabák genetika   virologie   MeSH
• viroidy genetika   patogenita   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• mediátorový komplex MeSH
• rostlinné proteiny MeSH

Paxillin (PXN) is a focal adhesion protein that has been implicated in signal transduction from the extracellular matrix. Recently, it has been shown to shuttle between the cytoplasm and the nucleus. When inside the nucleus, paxillin promotes cell proliferation. Here, we introduce paxillin as a transcriptional regulator of IGF2 and H19 genes. It does not affect the allelic expression of the two genes; rather, it regulates long-range chromosomal interactions between the IGF2 or H19 promoter and a shared distal enhancer on an active allele. Specifically, paxillin stimulates the interaction between the enhancer and the IGF2 promoter, thus activating IGF2 gene transcription, whereas it restrains the interaction between the enhancer and the H19 promoter, downregulating the H19 gene. We found that paxillin interacts with cohesin and the mediator complex, which have been shown to mediate long-range chromosomal looping. We propose that these interactions occur at the IGF2 and H19 gene cluster and are involved in the formation of loops between the IGF2 and H19 promoters and the enhancer, and thus the expression of the corresponding genes. These observations contribute to a mechanistic explanation of the role of paxillin in proliferation and fetal development.

• Klíčová slova
• Cohesin, Enhancer, H19, IGF2, Imprinting, Paxillin,
• MeSH
• buňky Hep G2 MeSH
• chromozomální proteiny, nehistonové genetika   MeSH
• extracelulární matrix genetika   MeSH
• fokální adheze genetika   MeSH
• genomový imprinting genetika   MeSH
• insulinu podobný růstový faktor II biosyntéza   genetika   MeSH
• koheziny MeSH
• lidé MeSH
• metylace DNA genetika   MeSH
• paxilin aplikace a dávkování   MeSH
• proliferace buněk účinky léků   genetika   MeSH
• promotorové oblasti (genetika) MeSH
• proteiny buněčného cyklu genetika   MeSH
• RNA dlouhá nekódující biosyntéza   genetika   MeSH
• signální transdukce účinky léků   MeSH
• vývoj plodu genetika   MeSH
• vývojová regulace genové exprese MeSH
• zesilovače transkripce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromozomální proteiny, nehistonové MeSH
• H19 long non-coding RNA MeSH Prohlížeč
• IGF2 protein, human MeSH Prohlížeč
• insulinu podobný růstový faktor II MeSH
• paxilin MeSH
• proteiny buněčného cyklu MeSH
• RNA dlouhá nekódující MeSH