Biology subjects

Turck, F. K.

Publications and source records attributed to Turck, F. K..

4 recordsLinked to original sources

bioRxiv2025

Epigenetic gene regulation is controlled by distinct regulatory complexes utilizing specialized paralogs of TELOMERE REPEAT BINDING FACTORS

Epigenetic regulators shape chromatin landscapes, allowing cells to express distinct gene sets depending on cell-type, developmental stage or environmental cues. These regulatory complexes rely on interactions with sequence-specific DNA binding proteins, such as the small family of TELOMERE REPEAT BINDING FACTORS (TRBs). TRBs are components of chromatin regulatory complexes with opposing functions, such as the epigenetic repressors Polycomb Repressive Complex 2 (PRC2) and a JMJ14/NAC complex that respectively add and removes the repressive H3K27me3 and positive H3K4me3 modification, but also with the plant-specific PEAT complex that is linked to histone acetylation and gene activation. We dissected the partial redundancy between TRB1, TRB2 and TRB3 in target gene selection and interaction with different chromatin regulatory complexes. High redundancy of TRBs is suggested by major phenotypic changes that are only observed trb triple mutants; however, we found different target site preference between TRB1-3 and preferred partnership with chromatin complexes. Furthermore, TRB paralogs interacted with the NuA4 histone acetylation complex, both together with and in absence of PEAT. Among the three paralogs, TRB1 had more unique binding sites and correlated stronger with PEAT and NuA4 functions. In contrast, TRB2 and TRB3 were more dependent on the presence of bona fide telo-box motifs and were more likely to be found at PRC2 associated sites. Overall, we provide insight into the diverse roles of TRBs in epigenetic gene regulation and how their diversification contributes to their apparent redundancy, as well as their observed activating and repressing effects on gene expression.

plant biology↗

bioRxiv2024

Characterization of FLOWERING LOCUS T related genes and their putative gene regulatory network in semi-winter Brassica napus cultivar Zhongshaung11

In many species, FLOWERING LOCUS T (FT)-like genes promote the floral transition by integrating environmental signals, in particular photoperiod, and internal cues. Here we show that Brassica napus contains 6 FT-like genes and 2 pseudogenes belonging to 3 orthogroups. All B. napus FT-like genes induce early flowering when expressed at the shoot apical meristems of Arabidopsis thaliana ft mutants, but BnaFT.C6 and non-orthologous FT-like genes do not encode fully functional mobile florigens. In the case of BnFT.C6, the functional change is associated with a T to C amino acid change that is restricted to semi-winter accessions. Expression of orthologs of FT is photoperiod-dependent and two distal enhancers are conserved; however, the homeologs BnaFT.A7 and BnaFT.C6 show rearrangements of DNA motifs binding NF-Y/CO and NF-Y transcriptional activator complexes between the promoter and downstream enhancers. Motif rearrangements correlate with differences in tissue-specific expression. Furthermore, homeologs with rearranged motifs could not be trans-activated by B. napus CO in transient assays although they genes show LD photoperiod-dependent expression. We propose that differential diurnal expression of NF-Y genes contributes to the photoperiod-dependent regulation of B. napus FT genes. Significance statementB. napus FT-like genes are a case study for gene retention and retraction after multiple rounds of polyploidisation. Retained B. napus FT-like genes show preferred expression in different developmental stages and amino-acid changes that affect florigen function.

plant biology↗

bioRxiv2024

Impact of mutations in the HEADING DATE 1 gene on transcription and cell wall composition of rice

Plants utilize environmental information to modify their developmental trajectories for optimal survival and reproduction. Over a century ago, day length (photoperiod) was identified as a major factor influencing developmental transitions, particularly the shift from vegetative to reproductive growth. In rice, exposure to day lengths shorter than a critical threshold accelerates flowering, while longer days inhibit this process. This response is mediated by HEADING DATE 1 (Hd1), a zinc finger transcription factor that is central in the photoperiodic flowering network. Hd1 acts as a repressor of flowering under long days but functions as a promoter of flowering under short days. However, the transcriptional organization of this dual function is still not fully understood. In this study, we utilized RNA-Seq to analyze the transcriptome of hd1 mutants under both long and short day conditions. We identified genes involved in the phenylpropanoid pathway that are deregulated under long days in the mutant. Quantitative profiling of cell wall components and abiotic stress assays suggest that Hd1 is involved in processes considered unrelated to flowering control. This indicates that day length perception and responses are intertwined with physiological processes beyond flowering.

plant biology↗

bioRxiv2021

AGL16 regulates genome-wide gene expression and flowering time with partial dependency on SOC1 in Arabidopsis

Flowering transition is pivotal and tightly regulated by complex gene-regulatory-networks, in which AGL16 plays important roles. But the molecular function and binding property of AGL16 is not fully explored in vivo. With ChIP-seq and comparative transcriptomics approaches, we characterized the AGL16 targets spectrum and tested its close molecular and genetic interactions with SOC1, the key flowering integrator. AGL16 bound to promoters of more than 2000 genes via CArG-box motifs that were highly similar to that of SOC1. Being consistent with this, AGL16 formed protein complex and shared a common set of targets with SOC1. However, only very few genes showed differential expression in the agl16-1 loss-of-function mutant, whereas in the soc1-2 knockout background, AGL16 repressed and activated the expression of 375 and 182 genes, respectively, with more than a quarter of the DEGs were also bound by AGL16. AGL16 targeted potentially to about seventy flowering time genes involved in multiple pathways. Corroborating with these, AGL16 repressed the flowering time stronger in soc1-2 than in Col-0 background. These data reveals that AGL16 regulates gene expression and flowering time with a partial dependency on SOC1 activity. Moreover, AGL16 participated in the regulation of water loss and seed dormancy. Our study thus defines the AGL16 molecular spectrum and provides insights underlining the molecular coordination of flowering and environmental adaptation.

plant biology↗