TY - JOUR
T1 - The direct effect of protein starvation on protein breakdown and synthesis in regions of the cultured early chick embryo
AU - Klein, Norman W.
AU - Yager, James D.
AU - Hagedorn, Karen
N1 - Funding Information:
*Scientific contribution No. 431 of the Agricultural Experiment Station, University of Connecticut. Contribution No. 190 of the Institute of Cellular Biology. This work was supported by the U.S. Atomic Energy Commission Contract No. AT(30-1)4030. A preliminary report of this work has been presented (Klein et al., 1969). This study was initiated at the Biology Department, Marquette University, Milwaukee, Wisconsin. *Graduate trainee in cellular biology, PHS grant GM 317, National Institute of General Medical Sciences.
PY - 1971/2
Y1 - 1971/2
N2 - Chick embryo explants of 11-13 somites (40 hours of preincubation) were exposed to14C-amino acids for 3 hours in liquid medium, cultured for 6 hours to reduce the trichloroacetic acid-soluble radioactive material, and then cultured on either protein starvation or growth media for periods up to 48 hours. The brain regions of explants cultured under starvation conditions lost larger quantities of radioactivity from protein than other regions of the embryo proper and the neural tube regions lost more radioactivity than the somites. The hearts of starved explants did not lose radioactivity. Explants cultured under growth conditions did not lose radioactivity from the regions of the embryo proper. Radioactivity was lost, however, from the protein of the extraembryonic membranes of explants cultured under both growth and starvation conditions. These basic observations were reproduced in experiments involving various14C-amino acids, the use of both growth and starvation conditions during the 6-hour preexperiment culture period, and the presence or absence of12C-amino acids in the final culture media. In an attempt to determine whether the regional differences in protein breakdown of starved explants were related to regional differences in protein synthesis, explants cultured for various periods on growth and starvation media were exposed to14C-amino acids for 90 and 180 minutes. The protein specific activities of embryo regions, corrected for regional differences in uptake and for the low overall specific activities of growing relative to starved explants, were comparable for growing and starved explants. This suggested that starvation did not differentially inhibit protein synthesis between regions of the embryo.
AB - Chick embryo explants of 11-13 somites (40 hours of preincubation) were exposed to14C-amino acids for 3 hours in liquid medium, cultured for 6 hours to reduce the trichloroacetic acid-soluble radioactive material, and then cultured on either protein starvation or growth media for periods up to 48 hours. The brain regions of explants cultured under starvation conditions lost larger quantities of radioactivity from protein than other regions of the embryo proper and the neural tube regions lost more radioactivity than the somites. The hearts of starved explants did not lose radioactivity. Explants cultured under growth conditions did not lose radioactivity from the regions of the embryo proper. Radioactivity was lost, however, from the protein of the extraembryonic membranes of explants cultured under both growth and starvation conditions. These basic observations were reproduced in experiments involving various14C-amino acids, the use of both growth and starvation conditions during the 6-hour preexperiment culture period, and the presence or absence of12C-amino acids in the final culture media. In an attempt to determine whether the regional differences in protein breakdown of starved explants were related to regional differences in protein synthesis, explants cultured for various periods on growth and starvation media were exposed to14C-amino acids for 90 and 180 minutes. The protein specific activities of embryo regions, corrected for regional differences in uptake and for the low overall specific activities of growing relative to starved explants, were comparable for growing and starved explants. This suggested that starvation did not differentially inhibit protein synthesis between regions of the embryo.
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U2 - 10.1016/0012-1606(71)90094-7
DO - 10.1016/0012-1606(71)90094-7
M3 - Article
C2 - 5553366
AN - SCOPUS:0015012138
SN - 0012-1606
VL - 24
SP - 178
EP - 197
JO - Developmental biology
JF - Developmental biology
IS - 2
ER -