| Popis: |
As we learned in the previous chapter, the eukaryotic genome exists in our cells as the nucleoprotein complex chromatin. A human cell contains approximately 40 million nucleosomes, which are the fundamental repeating units of chromatin. As expected for a highly conserved structure, such as that of the nucleosome, its assembly is tightly orchestrated. In this chapter, we learn how histone chaperone proteins help establish the formation of the nucleosomal structure from the core histones and DNA. One profound consequence of chromatin formation is blocked access of the cellular machineries that require intimate access to DNA for DNA replication, DNA repair and transcription. We present the current state of knowledge regarding how chromatin is locally disassembled to allow genomic processes to occur, and how it is then rapidly reassembled back into chromatin. As a whole, chromatin assembly not only enables the genome to be packaged to fit into our cells but also enables the regulation of all genomic functions through dynamic chromatin disassembly and reassembly. |
