Fig. 3. Quantitation of genomic in situ hybridization combined with SC35 immunostaining. The PLP gene and SC35 domains were scored as co-localized when there was pixel overlap in the red and green channels (see Fig. 2). SC35 domains are more frequently co-localized with the PLP gene in oligodendrocytes (oligos, n=110) compared with cells that do not transcribe detectable levels of PLP, i.e. astrocytes (astros, n=55), progenitors (OPs, n=116), and oligodendrocytes treated with -amanitin (oligos+AM, n=110) (P<0.05; Chi-square). As a control, the IRBP gene, which is not expressed in oligodendrocytes, had a frequency of PLP/SC35 co-localization similar to cells that do not express PLP (n=50). Error bars=standard error of the proportion.