3D medical animation from MediVisuals Inc. showing gene therapy to form bone from stem cells: Shows how an adenovirus capsid encounters receptors on cell membrane, then ruptures (lyses) while being transported by endosome vesicle to the nucleus. Liberated genome viral DNA travels to nucleus where mRNA (messenger RNA) is fabricated and, in the cytoplasm, manufactures BMP-2 protein which, when released by this host cell into intercellular space, attracts mesenchymal cells or stem cells (by chemotaxis) and attaches to their membranes, along with BMP-9 ligands; interior proteins meet these on the stem cell membrane and attract “smads” by phosphorylation. Smads move to nucleus and cause cell to proliferate and differentiate into chondrocytes; surrounding matrix forms bone. Less