Expression of pyruvate kinase in astrocytes induced to differentiate in vitro.
Astrocytes maintained in a chemically defined media undergo differentiation and a parallel increase in pyruvate kinase specific activity. These changes are accompanied by a shift in the isoelectrofocusing pattern, but not by expression of pyruvate kinase M4, the characteristic adult rat brain isozyme. Thus, this chemically defined media lacks a substance required to induce pyruvate kinase M synthesis and this function can be uncoupled from other aspects of cellular differentiation. The uncoupling of pyruvate kinase maturation from cellular differentiation and the observation of only a single, 2.3 kilobase, pyruvate kinase mRNA molecule at different stages of the postnatal development of rat brain support the concept that the K- to M-isoform transformation is a post-transcriptional event. The effect of the individual components of this chemically defined medium on pyruvate kinase specific activity was studied by eliminating one component at a time. The increase in activity was found to be completely dependent upon fibroblastic growth factor and prostaglandin F2 alpha and was partially dependent on the simultaneous presence of insulin.
Ngo
J L
JL
Department of Biological Chemistry, University of California, Irvine.
Ibsen
K H
KH
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology / Q000201:enzymology*; D001921:Brain / Q000201:enzymology / Q000254:growth & development; D002454:Cell Differentiation; D002478:Cells, Cultured; D003470:Culture Media; D004790:Enzyme Induction; D007527:Isoenzymes / Q000096:biosynthesis*; D024510:Muscle Development; D009132:Muscles / Q000201:enzymology; D011770:Pyruvate Kinase / Q000096:biosynthesis*; D051381:Rats; D013154:Spleen / Q000201:enzymology / Q000254:growth & development
D003470:Culture Media; D007527:Isoenzymes; D011770:Pyruvate Kinase