Carassius auratus-originated recombinant histone H1 C-terminal peptide as gene delivery material

The effective delivery of exogenous genes into eukaryotic cells is important for fundamental and biotechnological research. Protein-based gene delivery including histone proteins has recently emerged as a powerful technique for non-viral DNA transfer. Histones are DNA-binding proteins that function in DNA packaging and protection. In particular, histone H1 is largely responsible for the stabilization of higher-order chromatin structures. Several studies have examined the use of full-length histone H1-mediated gene transfer, and a few studies have investigated the use of C-terminal histone H1 fragments as gene-transfer materials. Previously, we cloned a novel histone H1 cDNA from the goldfish Carassius auratus and found that a recombinant histone H1 C-terminal short peptide (H1C) of 61 amino acids has comparable DNA binding and protection functions as full-length histone H1. In the present work, we successfully expressed and purified soluble recombinant H1C in an Escherichia coli expression system using a hexahistidine tag fusion strategy and providing tRNAs for rare codons. We confirmed its DNA-binding ability and found that this H1C peptide had similar or higher transfection efficiency in mammalian cells (human 293T and mouse NIH/3T3) than the widely used agent lipofectamine. Therefore, we suggest that this novel goldfish-derived recombinant histone H1 C-terminal short peptide could be used as a peptide-based gene-transfer mediator.