The nuclear matrix is a network of proteins that provides a structural framework for organising chromatin, while facilitating transcription and replication. Until recently attachment to the nuclear matrix was regarded as static, functionally segregating chromatin into loop domains. At present, a more dynamic model is being considered. In this model, cellular function and state-dependent interactions with the nuclear matrix provide a means by which segments of chromatin can acquire or maintain the open, potentiated conformation necessary for transcription. The human protamine gene cluster, and more recently, the human beta-gloin gene cluser have been used as model systems to address how matrix association may mediate the spatial and temporal patterns of gene expression.