Biology subjects

Lintermann, R.

Publications and source records attributed to Lintermann, R..

4 recordsLinked to original sources

bioRxiv2026

Epigenetic regulation of a heat-trainable sHSP locus controls thermomemory in a unicellular alga

A powerful way to enhance heat tolerance is to prime organisms with a moderate heat treatment to establish a molecular stress memory permitting the survival of the organism when exposed to subsequent heat shocks. While this has been extensively studied in multicellular organisms, we demonstrate that the unicellular red alga Cyanidioschyzon merolae exhibits heat stress memory. We show that, similarly to more complex organisms, thermomemory in this alga is underpinned by transcriptomic reprogramming, with the chloroplast emerging as the main site of gene trainability. Additionally, we find a conserved small heat shock protein (sHSP)-encoding locus in the nuclear genome to be heat-trainable, likely by histone depletion and sustained removal of the repressive mark histone H3 Lysine 27 trimethylation (H3K27me3). Of C. merolaes two sHSPs, only the nuclear-localizing CmsHSP2 is necessary for proper HS memory establishment. Finally, we reveal a role for the H3K27me3-transferase CmE(z) (Enhancer of zeste) in heat stress memory which shapes the transcriptome to recurring heat exposures, beyond regulating the trainable sHSP locus. Overall, our work provides a molecular framework for the regulation of heat stress memory in a unicellular eukaryote.

genetics↗

bioRxiv2021

The superior salinity tolerance of wheat cultivar Shanrong No. 3 cannot be attributed to elevated Ta-sro1 poly(ADP-ribose) polymerase activity

Saline soils limit the production of important staple crops such as wheat, particularly in arid and semiarid regions. Salt tolerance is a multi-gene trait and this complicates breeding of wheat varieties that deliver high yields under saline soil conditions. Notably, the elevated salinity tolerance of wheat cultivar Shanrong No. 3 (SR3) has been linked to a specific proteoform of the wheat SIMILAR TO RCD1 ONE (SRO1) protein that was created in an asymmetric genome hybridization with tall wheat grass. The two amino acid polymorphisms of the Ta-sro1 proteoform enhance the poly(ADP-ribose) polymerase (PARP) activity of the protein suggesting that altered poly-ADP-ribosylation of unknown substrate proteins or nucleic acids underlie the elevated salinity tolerance of cultivar SR3. To elucidate the molecular basis for the elevated PARP activity of the Ta-sro1 proteoform we solved a crystal structure of the catalytic PARP domain. Surprisingly, the structure revealed that the postulated binding site for the co-substrate NAD+ substantially differs from the structurally conserved NAD+ binding sites of canonical PARP enzymes. Consistently, we find that Ta-sro1 does not bind NAD+ and lacks ADP-ribosyltransferase activity. Therefore, although the structure revealed that one of the polymorphic amino acids is located close to the proposed active site, the elevated salinity tolerance of cultivar SR3 cannot be explained by altered ADP-ribosyltransferase activity of Ta-sro1.

plant biology↗

bioRxiv2018

Nuclear import of Arabidopsis POLY(ADP-RIBOSE) POLYMERASE 2 is mediated by importin-α and a nuclear localization sequence located between the predicted SAP domains

Proteins of the poly(ADP-ribose) polymerase (PARP) family modify target proteins by covalent attachment of ADP-ribose moieties onto amino acid side chains. In Arabidopsis, PARP proteins contribute to repair of DNA lesions and modulate plant responses to various abiotic and biotic stressors. Arabidopsis PARP1 and PARP2 are nuclear proteins and given that their molecular weights exceed the diffusion limit of nuclear pore complexes, an active import mechanism into the nucleus is likely. Here we use confocal microscopy of fluorescent protein-tagged Arabidopsis PARP2 and PARP2 deletion constructs in combination with site-directed mutagenesis to identify a nuclear localization sequence in PARP2 that is required for nuclear import. We report that in co-immunoprecipitation assays PARP2 interacts with several isoforms of the importin- group of nuclear transport adapters and that PARP2 binding to IMPORTIN-2 is mediated by the identified nuclear localization sequence. Our results demonstrate that PARP2 is a cargo protein of the canonical importin-/{beta} nuclear import pathway.

plant biology↗

bioRxiv2017

An Oomycete Effector Protein Induces Shade Avoidance In Arabidopsis And Attenuates Salicylate Signaling By Binding To Host Proteins Of The RADICAL-INDUCED CELL DEATH1 Family

The oomycete pathogen Hyaloperonospora arabidopsidis (Hpa) causes downy mildew disease on Arabidopsis. During infection, Hpa like other biotrophic pathogens, suppresses activation of plant innate immunity by translocating effector proteins into host cells. Some of these effectors localize to the host cell nucleus where they may manipulate transcriptional reprogramming of plant defense genes. Here we report that the nuclear-localized Hpa effector HaRxL106, when expressed in Arabidopsis, induces shade avoidance and attenuates the transcriptional response to the defense signaling molecule salicylic acid. HaRxL106 interacts with RADICAL-INDUCED CELL DEATH1 (RCD1) and loss of RCD1 function renders Arabidopsis resilient against HaRxL106-mediated suppression of immunity. To further characterize the molecular functions of RCD1 we solved a crystal structure of RCD1s Poly-(ADP-ribose)-Polymerase (PARP) domain and, based on non-conservation of amino acids constituting the active site of canonical PARPs, conclude that RCD1 has no PARP activity. We report that RCD1-type proteins are phosphorylated and identified histone-modifying Mut9-like kinases (MLKs) as RCD1-interacting proteins. A mlk1,3,4 triple mutant exhibits stronger SA-induced defense marker gene expression compared to wild-type plants. Our data suggest that HaRxL106 suppresses Arabidopsis innate immunity by manipulating the function(s) of RCD1 in the host cell nucleus and point towards a role of RCD1 as a transcriptional co-regulator that integrates signals from light and pathogen sensors.

plant biology↗