Translational stability of native and deadenylylated rabbit globin mRNA injected into HeLa cells.

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Abstract
HeLa [human cervical carcinoma] cells were injected with a natural mixture of rabbit .alpha. and .beta. globin mRNA. They were incubated for 6 h with [35S]methionine immediately after injection or 20 h later. The labeled proteins in the injected cells were analyzed by fluorography of 2-dimensional electrophoresis gels. By using this procedure, it was possible to show that during the 1st few hours after injection, both .alpha. and .beta. globin molecules are synthesized with an .alpha. to .beta. ratio of .apprx. 0.6. The rate of synthesis of .alpha. globin decreased significantly faster than that of .beta. globin over a 26 h period after injection of the 2 mRNA. It thus seems that the 2 mRNA coding for closely related polypeptides possess a markedly different translational stability. When deadenylylated rabbit globin mRNA were injected into HeLa cells, no globin synthesis could be detected by the techniques used. The translational half-life of mRNA lacking poly(A) is evidently very short in these cells. The poly(A)segment is apparently required to ensure the stability of globin mRNA in somatic cells as in Xenopus oocytes.