Abstract
Nuclear matrix is the residual structure after removing nuclear membrane and chromatin from isolated nuclei. Nuclear matrices of animals have three domains, lining of nuclear membrane, intranuclear network of fibrils, and residual nucleoli. Plant nuclear matrix is morphologically similar to those of animals, but at least the major constituent protein of the lining of nuclear membrane is different. Proteins in the internal fibrils have not yet been revealed in plants. Using monoclonal antibodies, we screened cDNA clones that encodes proteins existed in intranuclear network of fibrils of carrot nuclear matrix. One of the cloned cDNAs, 3F5-117had deduced amino acid sequence similar to Arabidopsis thaliana CDC5 (AtCDC5). CDC5 family is required for both cell cycle regulation and pre-mRNA splicing in the nucleus. Existence of a CDC5 homolog in plant nuclear matrix suggested that CDC5 may associate with the intranuclear network of fibrils.
