Dataset Information

The condensin complex is essential for amitotic segregation of bulk chromosomes, but not nucleoli, in the ciliate Tetrahymena thermophila.

ABSTRACT: The macronucleus of the binucleate ciliate Tetrahymena thermophila contains fragmented and amplified chromosomes that do not have centromeres, eliminating the possibility of mitotic nuclear division. Instead, the macronucleus divides by amitosis with random segregation of these chromosomes without detectable chromatin condensation. This amitotic division provides a special opportunity for studying the roles of mitotic proteins in segregating acentric chromatin. The Smc4 protein is a core component of the condensin complex that plays a role in chromatin condensation and has also been associated with nucleolar segregation, DNA repair, and maintenance of the chromatin scaffold. Mutants of Tetrahymena SMC4 have remarkable characteristics during amitosis. They do not form microtubules inside the macronucleus as normal cells do, and there is little or no bulk DNA segregation during cell division. Nevertheless, segregation of nucleoli to daughter cells still occurs, indicating the independence of this process and bulk DNA segregation in ciliate amitosis.

SUBMITTER: Cervantes MD

PROVIDER: S-EPMC1489118 | biostudies-literature | 2006 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The condensin complex is essential for amitotic segregation of bulk chromosomes, but not nucleoli, in the ciliate Tetrahymena thermophila.

Cervantes Marcella D MD Coyne Robert S RS Xi Xiaohui X Yao Meng-Chao MC

Molecular and cellular biology 20060601 12

The macronucleus of the binucleate ciliate Tetrahymena thermophila contains fragmented and amplified chromosomes that do not have centromeres, eliminating the possibility of mitotic nuclear division. Instead, the macronucleus divides by amitosis with random segregation of these chromosomes without detectable chromatin condensation. This amitotic division provides a special opportunity for studying the roles of mitotic proteins in segregating acentric chromatin. The Smc4 protein is a core compone ...[more]

PMID: 16738332

Similar Datasets

Project description:The ciliate Tetrahymena thermophila is a model organism for molecular and cellular biology. Like other ciliates, this species has separate germline and soma functions that are embodied by distinct nuclei within a single cell. The germline-like micronucleus (MIC) has its genome held in reserve for sexual reproduction. The soma-like macronucleus (MAC), which possesses a genome processed from that of the MIC, is the center of gene expression and does not directly contribute DNA to sexual progeny. We report here the shotgun sequencing, assembly, and analysis of the MAC genome of T. thermophila, which is approximately 104 Mb in length and composed of approximately 225 chromosomes. Overall, the gene set is robust, with more than 27,000 predicted protein-coding genes, 15,000 of which have strong matches to genes in other organisms. The functional diversity encoded by these genes is substantial and reflects the complexity of processes required for a free-living, predatory, single-celled organism. This is highlighted by the abundance of lineage-specific duplications of genes with predicted roles in sensing and responding to environmental conditions (e.g., kinases), using diverse resources (e.g., proteases and transporters), and generating structural complexity (e.g., kinesins and dyneins). In contrast to the other lineages of alveolates (apicomplexans and dinoflagellates), no compelling evidence could be found for plastid-derived genes in the genome. UGA, the only T. thermophila stop codon, is used in some genes to encode selenocysteine, thus making this organism the first known with the potential to translate all 64 codons in nuclear genes into amino acids. We present genomic evidence supporting the hypothesis that the excision of DNA from the MIC to generate the MAC specifically targets foreign DNA as a form of genome self-defense. The combination of the genome sequence, the functional diversity encoded therein, and the presence of some pathways missing from other model organisms makes T. thermophila an ideal model for functional genomic studies to address biological, biomedical, and biotechnological questions of fundamental importance.

Dataset Information

The condensin complex is essential for amitotic segregation of bulk chromosomes, but not nucleoli, in the ciliate Tetrahymena thermophila.

Publications

The condensin complex is essential for amitotic segregation of bulk chromosomes, but not nucleoli, in the ciliate Tetrahymena thermophila.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure