Abstract
Changes in the amounts of both mRNA and protein of glial fibrillary acidic protein (GFAP), the amounts Changes in the amounts of both mRNA and protein of glial fibrillary acidic protein (GFAP), the amounts of S-100 and laminin protein, and levels of IL-3R, IL-4R, and IL-6R mRNAs in newborn mouse astrocytes were examined during long-term, serial culture. The growth curve of isolated astrocytes showed an unusual pattern; that is, a very slow growth stage was followed by two successive stages of exponential growth separated by a short period of growth retardation. The specific astrocyte marker protein, GFAP, was detected until the end of the second stage. mRNA of IL-3R, an important molecule characteristic of astrocytes, was detected only during the first stage, whereas S100 and laminin proteins and IL-4R and IL-6R mRNAs were observed throughout the whole culture period. These results suggested that genes that specify the functions or phenotypes of astrocytes can be classified into several groups, and that the expression of the group containing IL-3R would be strictly related to the differentiated state of astrocytes.
