title: Chromosomal aneuploidies induced upon Lamin B2 depletion are mislocalized in the interphase nucleus.
abstract: Chromosome territories assume non-random positions in the interphase nucleus with gene-rich chromosomes localized toward the nuclear interior and gene-poor chromosome territories toward the nuclear periphery. Lamins are intermediate filament proteins of the inner nuclear membrane required for the maintenance of nuclear structure and function. Here, we show using whole-genome expression profiling that Lamin A/C or Lamin B2 depletion in an otherwise diploid colorectal cancer cell line (DLD1) deregulates transcript levels from specific chromosomes. Further, three-dimensional fluorescence in situ hybridization (3D-FISH) analyses of a subset of these transcriptionally deregulated chromosome territories revealed that the diploid chromosome territories in Lamin-depleted cells largely maintain conserved positions in the interphase nucleus in a gene-density-dependent manner. In addition, chromosomal aneuploidies were induced in ~25 % of Lamin A/C or Lamin B2-depleted cells. Sub-populations of these aneuploid cells consistently showed a mislocalization of the gene-rich aneuploid chromosome 19 territory toward the nuclear periphery, while gene-poor aneuploid chromosome 18 territory was mislocalized toward the nuclear interior predominantly upon Lamin B2 than Lamin A/C depletion. In addition, a candidate gene locus ZNF570 (Chr.19q13.12) significantly overexpressed upon Lamin B2 depletion was remarkably repositioned away from the nuclear lamina. Taken together, our studies strongly implicate an overarching role for Lamin B2 in the maintenance of nuclear architecture since loss of Lamin B2 relieves the spatial positional constraints required for maintaining conserved localization of aneuploid chromosome territories in the interphase nucleus.
authors.affiliation: Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India.
authors.forename: Devika
authors.initials: D
authors.lastname: Ranade
authors.affiliation: Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India.
authors.forename: Shivsmriti
authors.initials: S
authors.lastname: Koul
authors.affiliation: Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India.
authors.forename: Joyce
authors.initials: J
authors.lastname: Thompson
authors.affiliation: Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India.
authors.forename: Kumar Brajesh
authors.initials: KB
authors.lastname: Prasad
authors.affiliation: Biology, Indian Institute of Science Education and Research, Pune, Main Building, Homi Bhabha Road, Pashan, Pune, Maharashtra, 411008, India. kunsen@iiserpune.ac.in.
authors.forename: Kundan
authors.initials: K
authors.lastname: Sengupta
mesh_terms: D021581:Active Transport, Cell Nucleus; D000782:Aneuploidy; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism*; D004171:Diploidy; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D007399:Interphase / Q000235:genetics*; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism; D034921:Lamin Type B / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D034904:Lamin Type A; D034921:Lamin Type B; D034741:RNA, Small Interfering
keywords: Aneuploidy; Cancer cells; Chromosome positioning; Chromosome territories; Lamins; Nucleus; Transcription