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Conserved patterns of nuclear compartmentalization are not observed in the chordate Oikopleura
Author(s) -
Spada Fabio,
Koch Jeannette,
Sadoni Nicolas,
Mitchell Nadine,
Ganot Philippe,
Boni Umberto,
Zink Daniele,
Thompson Eric M.
Publication year - 2007
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1042/bc20060124
Subject(s) - biology , chordate , chromatin , heterochromatin , genome , nuclear lamina , chromosome conformation capture , histone , compartmentalization (fire protection) , gene , genomic organization , genetics , nuclear gene , crispr , microbiology and biotechnology , computational biology , evolutionary biology , enhancer , gene expression , transcription factor , nuclear protein , biochemistry , enzyme
Background information . Recent results from a limited number of eukaryotic model organisms suggest that major principles governing spatial organization of the genome in functionally distinct nuclear compartments are conserved through evolution. Results . We examined the in situ spatial organization of major nuclear components and nuclear patterns of gene loci with strictly defined expression patterns in endocycling cells of the transparent urochordate Oikopleura dioica , a complex metazoan with a very compact genome. Endocycling cells with different functions and similar DNA content displayed distinct topologies of nuclear components. However, the generation of the diverse nuclear architectures did not involve specific local organization of active genes or their preferential amplification. Interestingly, endocycling cells lacked nuclear‐envelope‐associated heterochromatin and prominent splicing‐factor domains, which in mammalian cells associate with transcriptionally silent and active loci respectively. In addition, no correlation was found between transcriptional activity of a locus and its association with chromatin domains rich in specific histone modifications. Conclusions . Together, these findings and the absence of typical eukaryotic replication patterns reveal a surprisingly limited functional compartmentalization of O. dioica endocycling nuclei. This indicates that robust cell‐type‐specific gene expression does not necessarily require high levels of spatial genome organization.