Parent cells must be able to divide in ways that create daughter cells that are different from each other, a process called asymmetric division.
Scientists know how this happens in animals, but the process in plants has been a mystery.
Now, Stanford biologists have found a plant protein that appears to play a key role in this type of cell division.
The presence of the protein, called BASL, is vital to asymmetric cell division. In plant cells where it was absent, the cells did not divide.
"This is crucial information if we really want to understand plants' unique ways of making the different types of cells in their bodies," said Dominique Bergmann, an assistant professor of biology.
Bergmann, along with Juan Dong, a postdoctoral researcher, and Cora MacAlister, a doctoral candidate, both in the Biology Department, tracked BASL in epidermal cells of Arabidopsis, a small plant used for genetic studies.
The epidermis of Arabidopsis contains small pores called stomata that allow the plant to breathe and these stomata are generated by asymmetric cell divisions.
"For asymmetric cell division in animals, we know many of the proteins that control the process, but plants just don't make any of those proteins," Bergmann said.
By following where in the cell BASL resides during successful asymmetric cell divisions, they have discovered that BASL behaves like many of the proteins vital for animal asymmetric cell divisions, even though BASL's structure doesn't look like any of them.
Bergmann, Dong, and MacAlister tracked BASL by adding a fluorescent tag that could be monitored under the microscope. This way, they could watch BASL as cells divided.
They found that BASL behaved in some ways like proteins involved in asymmetric animal cell division, that is, they observed BASL in both the nucleus and in a small region out near the periphery in cells that were about to divide asymmetrically.
After the division, only one cell inherited BASL at the cell periphery and this helped the two daughter cells become different.
When the instructions to make BASL were artificially put into any other cell in the plant, those cells not only made BASL, but the protein was found in both the nucleus and a small region at the periphery.
This proved that "all plant cells have within them the ability to put proteins in specialized areas," said Bergmann. (ANI)