Ed through a cell strainer, and centrifuged again. The cell suspension was loaded onto a step gradient of 35 and 60 Percoll (GE Healthcare UK Ltd., Little Chalfont, Buckinghamshire, UK) and centrifuged at 3,000 rpm for 20 min at room temperature. The large cell fraction was recovered from the 0 :35 interface, washed twice in washing buffer, and was used for cell isolation by FACS. The cells were suspended in 2 BSA/PBS at a density of 26107 cells/ml and labeled with PE-conjugated anti-CD44 antibody for 30 min in the dark on ice. The cells were then centrifuged at 1,000 rpm for 10 min and suspended in 2 BSA/PBS at 56106 cells/ml. To remove dead cells, 7-amino-actinomycin D (BD Biosciences) was added to the cell suspension (20 ml/106 cells). Cells were sorted by using a FACSAria 2 flow cytometer (BD Biosciences). There was overlap in the histogram of cell number vs fluorescence intensity of CD44 antibody staining (CD44-PE) between the CD44-positive population and the CD44-negative population (Fig. 1A left histograms). To 3PO site separate CD44-positive cells from CD44-negative 15481974 cells, side scatter (SSC) vs. CD44-PE (Fig. 1A Dot plots) and the gates to separate the CD44-negative population from the CD44positive population (reflected in the Fig. 1A right histograms) were determined. CD44high cells (about 5 of glial-enriched cellular fraction) and CD44low cells isolated by FACS were used for immunostaining and Neurosphere assay. CD44high cells and CD44low cells were cultured at 5 cells/ml in a 24-well plate (Falcon) in 500 ml of serum free media containing 10 ng/ml basic fibroblast growth factor (FGF2; Sigma) and 2 mg/ml heparin (Sigma). After 
7 days in vitro, numbers of floating sphere colonies (neurospheres) possessing a diameter of greater than 0.1 mm were counted.Materials and MethodsAll experiments were performed in accordance with the Guidelines for Animal Experimentation at Gunma University Graduate School of Medicine and were approved by the Gunma University Ethics Committee. We used more than 3 animals for each experiment to conclude the results.AnimalsC57BL6/NCr (SLC, Japan) (Fig. 1) or ICR strain mice (SLC, Japan) (Fig. 2?) were used throughout the studies. Embryos were collected at E12.5, E14.5, E16.5 and E18.5, and pups were collected at P3, P7, P10 and P14. Embryos (E14.5 18.5), pups, and adults (P42) were perfused Fexinidazole chemical information transcardially with phosphate buffered saline (PBS) followed by 4 paraformaldehyde (PFA) in PBS under deep anesthesia. Brains were further fixed in the same fixative over night at 4uC, and then immersed in PBS containing 20 sucrose. Brains fixed with 4 PFA were cut sagittally with a cryostat at a thickness of 18 mm.Immunostaining with Phycoerythrin-conjugated AntiCD44 AntibodyThe brain sections were washed with PBS, incubated for 30 min in TNB buffer (0.1 M Tris-HCl, 0.15 M NaCl, 0.5 Blocking regent), then incubated with phycoerythrin (PE)-conjugated rat anti-CD44 antibody (BD Biosciences, Clone name is IM7; diluted 1:200 in TNB buffer) overnight. After washing with PBS, the sections were examined with fluorescence microscopy (Axiovert 135, Zeiss, Germany).Double Immunostaining for CD44 and Cellular MarkersFixed brain sections were incubated in blocking buffer (3 BSA/PBS with 0.3 Triton X-100) and then were incubated with CD44 antibody (IM7, hybridoma supernatant; American Type Culture Collection; diluted 1:1000 in TNB buffer) for 2 hr. The sections were washed with PBS, incubated with biotin-conjugated anti-rat antib.Ed through a cell strainer, and centrifuged again. The cell suspension was loaded onto a step gradient of 35 and 60 Percoll (GE Healthcare UK Ltd., Little Chalfont, Buckinghamshire, UK) and centrifuged at 3,000 rpm for 20 min at room temperature. The large cell fraction was recovered from the 0 :35 interface, washed twice in washing buffer, and was used for cell isolation by FACS. The cells were suspended in 2 BSA/PBS at a density of 26107 cells/ml and labeled with PE-conjugated anti-CD44 antibody for 30 min in the dark on ice. The cells were then centrifuged at 1,000 rpm for 10 min and suspended in 2 BSA/PBS at 56106 cells/ml. To remove dead cells, 7-amino-actinomycin D (BD Biosciences) was added to the cell suspension (20 ml/106 cells). Cells were sorted by using a FACSAria 2 flow cytometer (BD Biosciences). There was overlap in the histogram of cell number vs fluorescence intensity of CD44 antibody staining (CD44-PE) between the CD44-positive population 
and the CD44-negative population (Fig. 1A left histograms). To separate CD44-positive cells from CD44-negative 15481974 cells, side scatter (SSC) vs. CD44-PE (Fig. 1A Dot plots) and the gates to separate the CD44-negative population from the CD44positive population (reflected in the Fig. 1A right histograms) were determined. CD44high cells (about 5 of glial-enriched cellular fraction) and CD44low cells isolated by FACS were used for immunostaining and Neurosphere assay. CD44high cells and CD44low cells were cultured at 5 cells/ml in a 24-well plate (Falcon) in 500 ml of serum free media containing 10 ng/ml basic fibroblast growth factor (FGF2; Sigma) and 2 mg/ml heparin (Sigma). After 7 days in vitro, numbers of floating sphere colonies (neurospheres) possessing a diameter of greater than 0.1 mm were counted.Materials and MethodsAll experiments were performed in accordance with the Guidelines for Animal Experimentation at Gunma University Graduate School of Medicine and were approved by the Gunma University Ethics Committee. We used more than 3 animals for each experiment to conclude the results.AnimalsC57BL6/NCr (SLC, Japan) (Fig. 1) or ICR strain mice (SLC, Japan) (Fig. 2?) were used throughout the studies. Embryos were collected at E12.5, E14.5, E16.5 and E18.5, and pups were collected at P3, P7, P10 and P14. Embryos (E14.5 18.5), pups, and adults (P42) were perfused transcardially with phosphate buffered saline (PBS) followed by 4 paraformaldehyde (PFA) in PBS under deep anesthesia. Brains were further fixed in the same fixative over night at 4uC, and then immersed in PBS containing 20 sucrose. Brains fixed with 4 PFA were cut sagittally with a cryostat at a thickness of 18 mm.Immunostaining with Phycoerythrin-conjugated AntiCD44 AntibodyThe brain sections were washed with PBS, incubated for 30 min in TNB buffer (0.1 M Tris-HCl, 0.15 M NaCl, 0.5 Blocking regent), then incubated with phycoerythrin (PE)-conjugated rat anti-CD44 antibody (BD Biosciences, Clone name is IM7; diluted 1:200 in TNB buffer) overnight. After washing with PBS, the sections were examined with fluorescence microscopy (Axiovert 135, Zeiss, Germany).Double Immunostaining for CD44 and Cellular MarkersFixed brain sections were incubated in blocking buffer (3 BSA/PBS with 0.3 Triton X-100) and then were incubated with CD44 antibody (IM7, hybridoma supernatant; American Type Culture Collection; diluted 1:1000 in TNB buffer) for 2 hr. The sections were washed with PBS, incubated with biotin-conjugated anti-rat antib.
