Cells of the baby hamster kidney (BHK) line express the skeletal muscle determining transcription factor MyoD but fail to differentiate. Unlike most skeletal myogenic cells, which express multiple members of the cadherin family of cell-cell adhesion proteins, the BHK cells lack a robust cadherin adhesion system. We previously published that forced expression of N- (or E)-cadherin in BHK cells increases the level of endogenous catenins, mediates strong cell-cell adhesion, and enhances differentiation of BHK cells induced to differentiate by placing them in three-dimensional (3-D) culture (Redfield et al. [1997] J. Cell. Biol. 138:1323-1331). This report demonstrates that N-cadherin adhesion upregulates the protein level of nuclear myogenin in cells induced to differentiate by 3-D culture. Myogenin is a transcription factor required for differentiation of skeletal muscle. It was not detected in monolayer culture, whether the cells expressed N-cadherin or not, nor was it upregulated in 3-D cultures of cells lacking N-cadherin. The activity of two myogenin-chloramphenicol acetyltransferase (CAT) reporter constructs containing 3.7 or 1.1 kb upstream regulatory region of the mouse myogenin gene was increased significantly in N-cadherin-expressing cells induced to differentiate by 3-D culture. Our observations indicate that N-cadherin adhesion stimulates skeletal myogenesis by upregulating myogenin.
Abstract— The localization of an acid lipase‐esterase which cleaves the fluorogenic substrate 4‐methyl‐umbelliferyl oleate at pH 5 was studied, because previous experiments has shown this activity to be reduced in the plaques of multiple sclerosis. In the human cerebellum, quantitative histochemical methods showed the activity to be relatively low in the molecular layer, compared to the granule cell layer; but the underlying white matter was the most active. In the human spinal cord, anterior horn cell bodies were richest in acid lipase, but white matter was, on a dry weight basis, as active as neuropil. Oligodendrocytes obtained in bulk from bovine white matter according to Poduslo & Norton (1972) had a specific activity up to 20 times greater than the crude myelin fraction. While it remains possible that in myelin the enzyme is in an inactive or inhibited state, the results indicate that the enzyme is localized in oligodendroglial cell bodies and suggest its use as a marker.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.