TFPI and osteosarcoma: In order to show functional co-recruitment of ORCA and the H3K9 KMTs, we used an in vivo cell system (CLTon) that uses a 200 copy transgene array-containing lac operator repeats stably integrated into human osteosarcoma (U2OS) cells as a single heterochromatic locus that can be visualized by Cherry-lac repressor (LacI).