Expanding the genetic code of the human hematopoietic system

Significance The ability to genetically incorporate noncanonical amino acids (ncAAs) into proteins in bacteria, yeast, mammalian cells, and multicellular organisms has provided useful tools to study and manipulate protein structure and function. Here, we report the development of a method to stably encode ncAAs in human hematopoietic stem cells (HSCs) and their differentiated progenies, using self-replicating plasmids derived from Epstein-Barr virus. We also demonstrate that once transplanted, these manipulated HSCs can give rise to the entire hematopoietic system encoded with ncAAs. The methods described here should be applicable to other progenitor cell populations and provide tools for the study of human proteins in vitro and in vivo.