text: One protein which regulates this substance is defective in ATRX syndrome.
full_question: One protein which regulates this substance is defective in ATRX syndrome. Rhabdoid tumors and choroid plexus carcinoma are linked to mutations in a gene which regulates this substance known as SMARCB1. ATP-dependent proteins which alter the structure of this substance include the ISWI, INO80, and NuRD protein families, which are "remodelers" of this substance. Proteins with a bromodomain motif recognize acetylated sites in this substance, which coils into a helical structure known as the 30 nm fiber. HP1 binds to the hetero- form of this material, which stains more darkly than its loosely-packed form. This substance is described as "beads on a string," where the beads are nucleosomes. It consists of interphase DNA wrapped around histones. For 10 points, name this substance involved in packaging and protecting cellular DNA which condenses to form chromosomes.
first_sentence: One protein which regulates this substance is defective in ATRX syndrome.
raw_answer: chromatin [or heterochromatin; or euchromatin; prompt on "DNA", "histones", "chromosomes", and "nucleosomes" until they are read]