Cell division orientation is the direction along which the new daughter

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

s are formed. Cell division orientation is important for

morphogenesis Morphogenesis (from the Greek ''morphê'' shape and ''genesis'' creation, literally "the generation of form") is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of deve ...

cell fate Within the field of developmental biology, one goal is to understand how a particular cell develops into a final cell type, known as fate determination. Within an embryo, several processes play out at the cellular and tissue level to create an organ ...

and tissue homeostasis. Abnormalities in the cell division orientation leads to the malformations during development and cancerous tissues. Factors that influence cell division orientation are cell shape, anisotropic localization of specific proteins and mechanical tensions.

Implication for morphogenesis

Cell division orientation is one of the mechanisms that shapes tissue during development and morphogenesis. Along with cell shape changes, cell rearrangements, apoptosis and growth, oriented cell division modifies the geometry and topology of live tissue in order to create new organs and shape the organisms. Reproducible patterns of oriented cell divisions were described during morphogenesis of ''Drosophila'' embryos, ''Arabidopsis thaliana'' embryos, ''Drosophila'' pupa, zebrafish embryos and mouse early embryos. Oriented cell divisions contribute to the tissue elongation and the release of mechanical stress. While in the first case oriented cell division acts as active contributor to the morphogenesis, the latter case is a passive response to the external mechanical tensions.

Implication for tissue homeostasis

In several tissues, such as columnar epithelium, the cells divide along the plane of the epithelium. Such divisions insert new formed cells in the epithelium layer. The disregulation of the orientation of cell divisions result in the creation of the cell out of epithelium and is observed at the initial stages of cancer.

Regulation

TCJ orients spindle apparatus during cell division

More than a century ago

Oskar Hertwig Oscar Hertwig (21 April 1849 in Friedberg – 25 October 1922 in Berlin) was a German embryologist and zoologist known for his research in developmental biology and evolution. Hertwig is credited as the first man to observe sexual reproduction ...

proposed that the cell division orientation is determined by the shape of the cell (1884), known as Hertwig rule. In the epithelium the cells 'reads' its shape through the specific

cell junction Cell junctions (or intercellular bridges) are a class of cellular structures consisting of multiprotein complexes that provide contact or adhesion between neighboring cells or between a cell and the extracellular matrix in animals. They also main ...

called tricellular junctions (TCJ). TCJ provide mechanical and geometrical clues for the

spindle apparatus In cell biology, the spindle apparatus refers to the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. It is referred to as the mitotic spindle during mitosis, a pr ...

to ensure that cell divide along its long axis. Several factors could regulate cell shape and therefore orientation of cell division. Among these factors is the anisotropic mechanical stress. This stress could be the result of the external mechanical deformation of generated intracellularly by non-isotropic localization of specific proteins.

References

{{Reflist Cell biology Cell anatomy Cell cycle Cellular processes Developmental biology Morphology (biology)