Matricin fibrils: isolation of the primary nuclear matrix polypeptides.

Matricin, a fundamental protein fibrillar structure of the eucaryotic cell nucleus, has been isolated from the rat liver nuclear matrix. The isolated matricin forms a diffuse reticulum of 30--50 A fibrils and consists predominantly of three primary polypeptide fractions with apparent molecular weights of 62,000, 66,000 and 70,000. Aside from a major role in nuclear structure, matricin may provide an important functional milieu for such fundamental nuclear processes as replication, transcription and the processing and transport of RNA.