Reddy stressed that understanding the function and regulation of stem-cell-specific genes is critical to gaining insights into basic questions such as what constitutes stem-cell identity (the ability of cells to remain unspecialized) and what makes them differentiate into specialized cells.
"A comparative analysis of stem-cell-specific genes between plant and animal systems may also lead to a better understanding of stem-cell identity, a concept common to both the systems," he said.
The study breaks ground also in the way Reddy's research team pinned down the stem-cell genes in Arabidopsis.
His lab initially labeled the three different SAM cell typesstem cells, niche cells and differentiating cellsby using different fluorescent proteins. Next, the researchers isolated the three discrete cell populations by first stripping the cell walls to release the cells as free populations. Then, using an instrument called Fluorescence Activated Cell Sorter, they separated each set of cells from the rest of the cell populations.
"Plant biologists have found it difficult to isolate the approximately 35 stem cells in the Arabidopsis shoot system for two main reasons: this is an extremely low number of stem cells and this clump of cells is tightly packed with a waxy coating covering its outer layer," Reddy said. "To meet this challenge, we used specific mutants of Arabidopsis that make more SAMs per plant. In the lab, we also formulated specific combinations of enzymes that efficiently digest away the cell walls."
Reddy explained that the gene expression map his team generated can help researchers track how genes give rise to complex tissues. It also will allow researchers to determine
|Contact: Iqbal Pittalwala|
University of California - Riverside