Short peptides as gene switches

Khavinson's group traced thymalin's action to short peptides like KE (Lys-Glu) and EW (Glu-Trp). These are small enough to enter the cell nucleus and bind DNA at gene promoters. There they change which genes for immune proteins and cytokines are read. This is the bioregulator idea: tiny tissue-specific peptides that restore the gene pattern of a young tissue.