Neuronal regulation of myelin basic protein mRNA translocation in oligodendrocytes is mediated by platelet-derived growth factor.

Translocation of mRNAs has emerged as an important form of protein targeting. In oligodendrocytes, the myelin-forming cells of the central nervous system, myelin basic protein (MBP) mRNAs are transported into cell processes and the cytoplasmic channels that infiltrate the myelin sheath. This mRNA movement is important for myelination and occurs in purified oligodendrocytes in vitro, but not in oligodendrocytes grown on bed layers of astrocytes.

Conditionally Immortalized Neural Cell Lines: Potential Models for the Study of Neural Cell Function.

Studies on primary cell cultures have contributed significantly to our understanding of neural cell function. Nevertheless, for many studies the value of these primary cell cultures has been limited by the time the cultures survive in vitro, the quantity of cellular material available for analysis, and the need to prepare the cells on a regular basis from fresh tissue. Techniques for immortalizing cells have existed for some time, but the repertoire of immortalizing genes has grown significantly.

5 beta-reductase and other androgen-metabolizing enzymes in primary cultures of developing zebra finch telencephalon.

Enzymes in the avian brain irreversibly catalyze the conversion of androgens into either active metabolites (aromatase and 5 alpha-reductase) or inactive metabolites (5 beta-reductase), 5 beta-reductase is thought to influence the formation of active metabolites by reducing the concentration of androgenic substrate available for these reactions. However, because these enzymes have different regional, cellular and subcellular distributions in brain, the traditional method to measure enzyme activity in brain homogenates may be inaccurate because of artificial mixing of enzymes. Recently, we have prepared primary cell cultures from the telencephalons of developing zebra finches.

Neuronal and non-neuronal aromatase in primary cultures of developing zebra finch telencephalon.

Estrogenic metabolites of circulating androgens have important effects on the organization and activation of neural circuits controlling reproductive behavior and physiology in males of many vertebrate species. Previous studies indicate that aromatase, the enzyme that converts androgens to estrogens, is expressed most abundantly in neurons in limbic brain regions. Songbirds are unique in that aromatase is expressed at unusually high levels throughout the telencephalon of both males and females.

Myelin basic protein mRNA translocation in oligodendrocytes is inhibited by astrocytes in vitro.

Myelin basic protein (MBP) mRNAs are translocated from cell bodies into the slender processes connecting oligodendrocyte somas with the myelin sheath in vivo. This translocation was observed in mixed glial cultures prepared from newborn mouse brains and it occurred in approximately 25% of the cells expressing the gene. However, when "enriched" oligodendrocytes were prepared by shaking them free of other glial cells, MBP mRNA translocation occurred into the processes of essentially all of the cells.