Nuclear Dualism

• Published in: Methods in Cell Biology Vol. 109; pp. 29 - 52
• Main Author: Karrer, Kathleen M.
• Format: Book Chapter Journal Article
• Language: English
• Published: United States Elsevier Science & Technology 2012
• Subjects: Alignment; Allele; Assortment; Chromatin - genetics; Chromatin - metabolism; Chromosome Breakage; Chromosomes - genetics; Chromosomes - metabolism; DNA Methylation; DNA, Protozoan - genetics; DNA, Protozoan - metabolism; Dualism; Genome, Protozoan; Histones - genetics; Histones - metabolism; Macronucleus - genetics; Macronucleus - metabolism; Micronucleus; Micronucleus, Germline - genetics; Micronucleus, Germline - metabolism; Mitosis; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Reproduction; Telomere; Telomere - genetics; Telomere - metabolism; Tetrahymena - genetics; Tetrahymena - metabolism; Transcription, Genetic; Alignment; Allele; Assortment; Telomere; Micronucleus; Dualism
• ISBN: 0123859670; 9780123859679
• ISSN: 0091-679X
• DOI: 10.1016/B978-0-12-385967-9.00003-7

Nuclear dualism is a characteristic feature of the ciliated protozoa. Tetrahymena have two different nuclei in each cell. The larger, polyploid, somatic macronucleus (MAC) is the site of transcriptional activity in the vegetatively growing cell. The smaller, diploid micronucleus (MIC) is transcriptionally inactive in vegetative cells, but is transcriptionally active in mating cells and responsible for the genetic continuity during sexual reproduction. Although the MICs and MACs develop from mitotic products of a common progenitor and reside in a common cytoplasm, they are different from one another in almost every respect.