The nuclear matrix: Structure, function and dna replication

This chapter discusses the structure, function, and DNA replication of the nuclear matrix. Standard thin sectioning and heavy metal staining reveals several major components in the cell nucleus: deeply stained, transcriptionally inactive heterochromatin, the nucleolus, a surrounding double-membraned nuclear envelope inundated with nuclear pore complexes and a diffuse in situ matrix region. A schematic three-dimensional view of the typical eukaryotic cell nucleus is presented in the chapter. In this model, the in situ matrix is presented as the major structural region in the nucleus, where nuclear function occurs. Nuclear matrix has been related to the nuclear functions of replication, transcription, and RNA processing and transport to the cytoplasm. In support of this conclusion, a direct relationship between the relative amount of nonchromatin nuclear matrix in the nucleus and the transcriptional activity of the cell has been observed. It is suggested that both the matrix and nuclear functions make and drive each other in a sort of unified symbiosis at the supramolecular level.