Preprophase tape is a microtubule ring found in plant cells undergoing division and entering the preprophase phase of the cell cycle of plant cells. Apart from the fragmosomes , the preprophase ribbon is the first structure visible under the microscope in plant cells that enter mitosis .
Content
History
For the first time, preprophase tape was seen and described by Jeremy Pickett-Heaps and Donald Northcote of Cambridge University in 1966 [1] .
Structure
Immediately after the onset of mitosis, the preprophase ribbon forms as a thick ring of microtubules surrounding the fragmosome, which outlines the plane of future division and is located immediately below the plasma membrane . It surrounds the core at the equator of the future spindle of division. The preprophase tape consists of microtubules and actin filaments. When a preprophase ribbon is labeled with fluorescent dyes , it is visible as two yellow spots located close to the cell wall on both sides of the nucleus.
Cell cycle participation
Plant cells do not have centrosomes , and therefore they cannot fulfill the role of microtubule organization centers . Instead, the microtubules of the mitotic spindle collect on the surface of the nucleus and reorient at the end of the prophase , forming a spindle. The preprophase ribbon also directly participates in the orientation of the mitotic spindle and contribute to the formation of the spindle during prometaphase [2] .
The preprophase ribbon is destroyed when the nuclear membrane is destroyed and a spindle is formed, leaving a zone of poor actin. However, her position also marks the future site of the formation of a new cell plate and a new cell wall during telophase . When mitosis is completed, a new cell plate and cell wall begin to form from the center along the plane outlined by the fragmosome. The cell plate grows outward until it merges with the cell wall of the dividing cell, and it is in those spots that the preprophase tape noted.
Notes
- ↑ Pickett-Heaps JD, Northcote DH Organization of microtubules and endoplasmic reticulum during mitosis and cytokinesis in wheat meristems (Eng.) // Journal of Cell Science : journal. - The Company of Biologists , 1966. - Vol. 1 , no. 1 . - P. 109-120 . - PMID 5929804 .
- ↑ Ambrose JC, Cyr RJ Mitotic spindle organization by the preprophase band (Eng.) // Molecular Plant: journal. - 2008 .-- Vol. 1 , no. 6 . - P. 950-960 . - DOI : 10.1093 / mp / ssn054 . - PMID 19825595 . Archived on April 15, 2013.
Literature
- PH Raven, RF Evert, SE Eichhorn (2005): Biology of Plants , 7th Edition, WH Freeman and Company Publishers, New York, NY, ISBN 0-7167-1007-2
- L. Taiz, E. Zeiger (2006): Plant Physiology , 4th Edition, Sinauer Associates, Inc., Publishers, Sunderland, MA, ISBN 0-87893-856-7