Abstract

Analysis of the DNA sequence associated with the nuclear matrix has made it possible to identify several types of DNA matrix association. Permanent attachment sites are detected in both transcriptionally active and inactive nuclei. Furthermore, replication origins have been shown to be permanently attached to the nuclear matrix. In transcriptionally active nuclei, expressed genes are also associated with the nuclear matrix. Finally, a special group of attachment sites is described; these sites are believed to maintain the fixed positions of individual chromosomes in interphase nuclei.