Abstract:
:Chick-limb mesodermal cells have been maintained in tissue culture under conditions that permit development of muscle and cartilage. 3-Acetylpyridine, a nicotinamide-antagonized muscle teratogen, potentiates chondrogenic expression in cell cultures, as evidenced by histological and biochemical criteria, including the production of chondromucoprotein. Xylosyltransferase and N-acetylgalactosaminyltransferase are two enzymes required for chondromucoprotein synthesis; the specific activities of these enzymes were measured in differentiating mesodermal cells cultured for various periods of time in the presence and absence of 3-acetylpyridine and in intact limb tissue. The ratios of specific enzyme activities were nearly the same in both cultured cells and limb tissue, although the levels of both transferases increased severalfold during chondrogenic expression by mesodermal cells in culture. 3-Acetylpyridine causes the specific activities of xylosyl- and N-acetylgalactosaminyltransferases to increase 10- and 2-fold, respectively, above those of untreated cultures. Compared to the ratio of transferase activities in limb tissue and differentiating cell cultures, 3-acetylpyridine appears to increase the activity of xylosyltransferase, the initiator of chondroitin sulfate chain synthesis, more than does N-acetylgalactosaminyltransferase; this finding implies that the synthesis of these two enzymes may be separately regulated.
journal_name
Proc Natl Acad Sci U S Aauthors
Caplan AI,Stoolmiller ACdoi
10.1073/pnas.70.6.1713subject
Has Abstractpub_date
1973-06-01 00:00:00pages
1713-7issue
6eissn
0027-8424issn
1091-6490journal_volume
70pub_type
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