ISSN:
0021-9541
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Cultured rat embryo cells exposed to the L-arginine analogue L-canavanine rapidly accumulated a major 71 kilodalton polypeptide and several minor ones (110, 95, 88, and 78 kilodaltons). Canavanine-treated cultures contained elevated levels of translatable mRNA encoding P71, and the stimulated synthesis of this protein was blocked by actinomycin D, suggesting that P71 is inducible. Rat embryo cells maintained under routine culture conditions synthesized only trace amounts of P71; however, they accumulated an abundant 73 kilodalton protein that was closely related to P71. No kinetic evidence of a precursor-product relationship between P73 and P71 was found. The peptide map of P71 from cultured cells was identical to the map of proteins with the same electrophoretic mobility isolated from incubated slices of rat telencephalon. Previous studies (White, ′80a, b, c) have shown that the latter proteins are rapidly synthesized by cells associated with cerebral microvessels in incubated brain slices, but are not detectable in vivo. Herein we present evidence that the synthesis of P71 is not unique to brain slices. Incubated slices of heart, lung, thymus, kidney, spleen, and liver all accumulated an abundant 71 kilodalton size class. The peptide maps of P71 obtained from brain, heart, lung, and thymus tissue were similar. The stimulated synthesis of P71 in brain, heart, and lung slices was inhibited strongly by the addition of actinomycin D at the start of incubation. The 71-73 kilodalton proteins of canavanine-treated rat embryo cells and incubated slices from seven different organs were compared in detail on two-dimensional poly-acrylamide gels. Eight charge variants were detected in extracts of lung, spleen, and thymus tissue, four in liver and heart, three in kidney, and two different pairs of variants in extracts of brain tissue and cultured cells. The possible significance of the rapid synthesis of a similar small set of proteins in tissue slices and cultured cells in response to a variety of physical, chemical, and biological stimuli is discussed in terms of cellular responses to traumatic injury and metabolic stress.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1041080216
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