Novel protein critical for cellular proliferation discovered
Accurate duplication of genetic material and the faithful segregation of chromosomes are critical for cell survival. The initiation of DNA replication is linked both to cell cycle progression and chromatin organization. In plants, animals and other "eukaryotes," the assembly of a multi-protein complex called pre-replicative complex (preRC) is the first step in the initiation of DNA replication. As the name implies, origin recognition complex (ORC) proteins bind to origins of DNA replication. Subsequently, other components of preRC are assembled at these sites. In addition to its role in DNA replication, ORC is also involved in gene silencing and organization of the tightly packed DNA, called heterochromatin. How ORC is brought to the DNA in human cells had previously remained a mystery.