The chicken lysozyme locus is regulated in oviduct and macrophages by a complex set of well-characterized cis-regulatory DNA elements. We determined the DNase I hypersensitive chromatin site pattern of the chromatin of the lysozyme locus in retrovirally transformed cell lines representing different stages of myelomonocytic cell differentiation. In the transformed multipotent progenitor stage and in erythroblasts, only a DNase I hypersensitive chromatin site at a silencer element located -2.4 kb upstream of the transcriptional start site is present. At the myeloblast stage DNase I hypersensitive chromatin sites are formed both at the distal enhancer located at -6.1 kb and at the promoter. Later in differentiation, at the monocytic stage, a second DNase I hypersensitive chromatin site appears at the medial enhancer located at -2.7 kb. Parallel with DNase I hypersensitive chromatin site formation at the medial enhancer, the DNase I hypersensitive chromatin site at the silencer element disappears. These chromatin rearrangements correlate with the mRNA expression of the gene that is undetectable in multipotent progenitors and maximal in a lipopolysaccharide-stimulated monocyte cell line. Our results show that the chromatin structure and the transcriptional activity of the gene are tightly coupled during commitment and maturation of the myelomonocytic lineage.

The molecular structuring of complex architectures and the enclosure of space are essential requirements for technical and living systems. Self‐assembly of supramolecular structures with desired shape, size, and stability remains challenging since it requires precise regulation of physicochemical and conformational properties of the components. Here a general platform for controlled self‐assembly of tailored amphiphilic elastin‐like proteins into desired supramolecular protein assemblies ranging from spherical coacervates over molecularly defined twisted fibers to stable unilamellar vesicles is introduced. The described assembly protocols efficiently yield protein membrane–based compartments (PMBC) with adjustable size, stability, and net surface charge. PMBCs demonstrate membrane fusion and phase separation behavior and are able to encapsulate structurally and chemically diverse cargo molecules ranging from small molecules to naturally folded proteins. The ability to engineer tailored supramolecular architectures with defined fusion behavior, tunable properties, and encapsulated cargo paves the road for novel drug delivery systems, the design of artificial cells, and confined catalytic nanofactories.

The control over the defined assembly of nano-objects with nm-precision is important to create systems and materials with enhanced properties, for example, metamaterials. In nature, the precise assembly of inorganic nano-objects with unique features, for example, magnetosomes, is accomplished by efficient and reliable recognition schemes involving protein effectors. Here we present a molecular approach using protein-based 'adaptors/ connectors' with genetically encoded interaction sites to guide the assembly and functionality of different plasmonically active gold nanoparticle architectures (AuNP). The interaction of the defined geometricaly shaped protein adaptors with the AuNP induces the self-assembly of nanoarchitectures ranging from AuNP encapsulation to one-dimensional chain-like structures, complex networks and stars. Synthetic biology and bionanotechnology are applied to co-translationally encode unnatural amino acids as additional site-specific modification sites to generate functionalized biohybrid nanoarchitectures. This protein adaptor-based nanoobject assembly approach might be expanded to other inorganic nano-objects creating biohybrid materials with unique electronic, photonic, plasmonic and magnetic properties.

Phospholipid membranes are essential constituents of extant cells rendering them preferred candidates as membrane components in origin of life scenarios. These models greatly neglect stability requirements and their problematic synthetic complexity necessary to access such lipid membrane constituents under early life conditions. Here we present an alternative protocell model, based on amphiphilic protein membranes constituted of prebiotic amino acids. These self-assembled dynamic Protein Membrane Based Compartments (PMBC) are impressively stable and compatible with prevalent protocell membrane constituents. PMBCs can enclose functional proteins, undergo membrane fusion, phase separate, accommodate anabolic ligation reactions and DNA encoded synthesis of their own membrane constituents. Our findings suggest that prebiotic PMBC represent a new type of protocell as plausible ancestor of current lipid-based cells. They can be used to design simple artificial cells important for the study of structural and catalytic pathways related to the emergence of life.

No abstract