An Engineered Toolkit for Precise Spatiotemporal Regulation of Protein Nucleo-cytoplasmic Distribution Derived From Programmable RfA1 Sequence

Proteins, as gifts from nature, provide structure, sequence, and function templates for designing biomaterials. Here, we reported an engineered toolkit derived from a natural block copolymer, RfA1. RfA1 is composed of positively charged polyelectrolyte linker regions interspersed with highly conserved polyampholyte motifs. These linkers and motifs are constructional fragments and ready-to-use building blocks for synthetic design and construction. One functional and editable feature of RfA1 derivatives is their preferential distribution to cytoplasm or nucleoplasm, in a fragment-replication-determined manner. Based on this property, a prices spatiotemporal Tet-on demo was established, which effectively transports cargo peptides into nuclei at selective time points. Moreover, the functional homogeneities of either motifs or linkers were also verified, making them standardized building blocks for synthetic biology. In summary, this study provides a modularized, orthotropic and well-characterized toolkit for precise and spatiotemporal regulation of protein nucleocytoplasmic localization.