( Scientists at the University of Michiga...)U-M scientists discover identifying markers for primitive blood-forming stem cells

By reading the bar code, scientists can separate stem cells from their more advanced descendants ?progenitor cells that already are committed to becoming one type of blood cell. The secret, according to U-M scientists, is to look for the presence or absence of cell surface receptor proteins expressed by a family of genes called SLAM.

Scientists knew that the 10 or 11 genes in the SLAM family helped regulate the development and activation of white blood cells called lymphocytes, but no one knew they also were associated with hematopoietic stem cells.

"SLAM is the first family of receptors whose patterns of gene expression can be used to precisely distinguish hematopoietic stem cells from progenitor cells, and to identify stem cells in tissue sections," says Sean Morrison, Ph.D., an associate professor of internal medicine and of cell and development biology in the U-M Medical School and a Howard Hughes Medical Institute investigator.

Results of the research study will be published in the July 1 issue of Cell.

The discovery will be valuable to scientists working in the rapidly advancing field of stem cell science. Currently, scientists must search for many different markers and use complex procedures to separate rare hematopoietic stem cells, or HSCs, from other cells in a blood sample. Using SLAM markers will streamline the process considerably, says Mark J. Kiel, a student in the U-M Medical School's M.D./Ph.D. program who is co-first author of the study.

"The classical markers work, but they are complex and it takes a high level of skill to obtain a pure sample of HSCs," Kiel says. "We showed that using just two SLAM marker
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Source:University of Michigan Health System