Biology subjects

Moldt, M.

Publications and source records attributed to Moldt, M..

4 recordsLinked to original sources

bioRxiv2026

Sequence-dependent binding modes of INO80 control +1 nucleosome positioning

Cellular self-organisation counteracts entropy at the expenditure of energy. In case of the first level of nuclear DNA organisation, this relates to regular nucleosome arrays and interspaced nucleosome-depleted regions (NDRs), for example at promoters or replication origins1-5. The organisation of nucleosomes as building blocks of chromatin is orchestrated by the collective activities of ATP-dependent chromatin remodellers6-9. Yet, how remodellers achieve positional specificity, in particular regarding the promoter-proximal +1 nucleosomes, remains unclear. Here, we show that the S. cerevisiae chromatin remodeller INO80 unexpectedly distinguishes DNA sequence asymmetry within the +1 nucleosome of the SWH1 gene through distinct inhibited and active nucleosome-binding modes. In structural and biochemical analyses of INO80 on nucleosomes with the endogenous sequence, we identified an inhibited binding mode where the entire INO80 remodelling unit flipped on the +1 nucleosome. INO80 adopted this remodelling-incompetent binding mode when facing the promoter, but a remodelling-competent mode when facing the gene body. This directional read-out of intra-nucleosomal DNA sequence asymmetry, together with extranucleosomal NDR sequence features, prevented nucleosome sliding into the NDR while permitting array formation over the gene. Our work shows how DNA features contribute to ATP-dependent self-organisation of promoter chromatin by INO80.

biochemistry↗

bioRxiv2025

Recognition and remodelling of nucleosomes and hexasomes by the human INO80 complex

The ATP-dependent INO80 chromatin remodeller slides and repositions nucleosomes to shape and maintain chromatin around gene regulatory elements and replication origins. Recent work uncovered capabilities of yeast and fungal INO80 to bind and slide hexasomes, but whether this is a universal feature is unknown. Here, we show that also human INO80 slides hexasomes as efficiently as H2A and H2A.Z nucleosomes. By determining a variety of structures of human INO80 bound to canonical and H2A.Z nucleosomes as well as hexasomes, we reveal a predominantly topological sensing of nucleosomal species with at least three positions depending on entry DNA unwrapping. INO80 spin-rotates around the wheel like nucleosomal core particle, with the position determined by the Snf2 ATPase that binds the tangentially protruding entry DNA at various degrees of unwrapping. Acidic patch binding by IES2 can differentiate between different nucleosomal species, is important for nucleosome but not hexasome sliding, and can sense unwrapped exit DNA. These findings provide structural and mechanistic insights into how human INO80 remodels diverse chromatin substrates in a topology driven manner.

biochemistry↗

bioRxiv2020

Genome information processing by the INO80 chromatin remodeler positions nucleosomes

The fundamental molecular determinants by which ATP-dependent chromatin remodelers organize nucleosomes across eukaryotic genomes remain largely elusive. Here, chromatin reconstitutions on physiological, whole-genome templates reveal how remodelers read and translate genomic information into nucleosome positions. Using the yeast genome and the multi-subunit INO80 remodeler as a paradigm, we identify DNA shape/mechanics encoded signature motifs as sufficient for nucleosome positioning and distinct from known DNA sequence preferences of histones. INO80 processes such information through an allosteric interplay between its core- and Arp8-modules that probes mechanical properties of nucleosomal and linker DNA. At promoters, INO80 integrates this readout of DNA shape/mechanics with a readout of co-evolved sequence motifs via interaction with general regulatory factors bound to these motifs. Our findings establish a molecular mechanism for robust and yet adjustable +1 nucleosome positioning and, more generally, remodelers as information processing hubs that enable active organization and allosteric regulation of the first level of chromatin.

biochemistry↗

bioRxiv2020

Ruler elements in chromatin remodelers set nucleosome array spacing and phasing

Arrays of regularly spaced nucleosomes dominate chromatin and are often phased by alignment to reference sites like active promoters. How the distances between nucleosomes (spacing), and between phasing sites and nucleosomes are determined remains unclear, and specifically, how ATP dependent chromatin remodelers impact these features. Here, we used genome-wide reconstitution to probe how Saccharomyces cerevisiae ATP dependent remodelers generate phased arrays of regularly spaced nucleosomes. We find that remodelers bear a functional element named the ruler that determines spacing and phasing in a remodeler-specific way. We use structure-based mutagenesis to identify and tune the ruler element residing in the Nhp10 and Arp8 modules of the INO80 remodeler complex. Generally, we propose that a remodeler ruler regulates nucleosome sliding direction bias in response to (epi)genetic information. This finally conceptualizes how remodeler-mediated nucleosome dynamics determine stable steady-state nucleosome positioning relative to other nucleosomes, DNA bound factors, DNA ends and DNA sequence elements.

biochemistry↗