Preprophase band

A structure in plant cells that predicts the future plane of cell division

Preprophase Band

The preprophase band is a microtubule structure found in plant cells that plays a crucial role in determining the plane of cell division. It is a transient structure that appears during the G2 phase of the cell cycle and disappears before the onset of mitosis.

Diagram of a plant cell showing the preprophase band (PPB) in green.

Formation

The preprophase band forms as a ring of microtubules and actin filaments beneath the plasma membrane of the cell. It encircles the nucleus and marks the future division plane. The formation of the preprophase band is a key event in the preparation for cytokinesis, as it predicts where the new cell wall will form between the two daughter cells.

Function

The primary function of the preprophase band is to establish the division site. It acts as a spatial marker that guides the assembly of the phragmoplast, a structure that directs the formation of the new cell wall. The preprophase band ensures that the division plane is correctly oriented, which is essential for maintaining the proper shape and function of plant tissues.

Disassembly

The preprophase band disassembles as the cell enters prophase, the first stage of mitosis. Although the band itself disappears, the positional information it provides is retained by the cell, guiding the subsequent stages of cell division.

Significance

The preprophase band is unique to plant cells and is not found in animal cells. Its presence is a key feature of plant cell division, reflecting the importance of precise spatial control in the development of plant tissues. The orientation of cell division, as determined by the preprophase band, influences the overall architecture of the plant.

Related pages

• Mitosis
• Cytokinesis
• Phragmoplast
• Microtubule
• Cell cycle