Leukocyte Nucleus Reveals a Linear Order of Chromosomes Separated in Two Parental Genomes That Favors the Process of Gene Activation.

Analysis of trisomy 8 cells and the chromosome-specific fluorescence in situ hybridization (FISH) signals on the ring-shaped nucleus of a neutrophil reveal that homologue chromosomes orient in diametrical opposition to each other. This positioning results in a separation of the two haploid sets of parental chromosomes organized as two exclusive groups. These two groups impart the nucleus a symmetry that fortifies immune protection by accelerating chemotaxis.

Chromosomes in a genome-wise order: evidence for metaphase architecture.

Background: One fundamental finding of the last decade is that, besides the primary DNA sequence information there are several epigenetic "information-layers" like DNA-and histone modifications, chromatin packaging and, last but not least, the position of genes in the nucleus.

Results: We postulate that the functional genomic architecture is not restricted to the interphase of the cell cycle but can also be observed in the metaphase stage, when chromosomes are most condensed and microscopically visible. If so, it offers the unique opportunity to directly analyze the functional aspects of genomic architecture in different cells, species and diseases.

Nuclear segmentation, condensation and bilateral symmetry in polymorphonuclear leukocytes reflect genomic order and favor immunologic function.

Segmentation, condensation and bilateral symmetry of the nuclei of polymorphonuclear leukocytes seem related to their function. Segmentation of the nuclei into two or more lobes and their condensation facilitate their passage (diapedesis) through the endothelial layer of blood vessels to the extravasal space and subsequent locomotion through the interstitial compartment of different tissues. Bilateral symmetry of these nuclei along with their association to the cytoskeletal fibers contribute to their efficiency in locomotion by alignment of the axis of nuclear symmetry to the axis of cellular polarity, which orients towards the direction of locomotion in response to cytokines and other stimuli.

Biphasic chromatin structure and FISH signals in reflect intranuclear order.

Background And Aim: One of the two parental allelic genes may selectively be expressed, regulated by imprinting, X-inactivation or by other less known mechanisms. This study aims to reflect on such genetic mechanisms.

Materials And Methods: Slides from short term cultures or direct smears of blood, bone marrow and amniotic fluids were hybridized with FISH probes singly, combined or sequentially.