Krowczynska A, Yenofsky R, Brawerman G
J Mol Biol. 1985 Jan 20;181(2):231-9. doi: 10.1016/0022-2836(85)90087-7.
The decay rates of several messenger RNA species were determined in mouse erythroleukemia cells. The t1/2 values for the actin and tubulin mRNAs were 16 to 26 hours and about seven hours, respectively. The globin mRNA, and two mRNA species subject to translation repression, the P40 and P21 mRNAs, were about as stable as the ribosomal RNA. A stable tubulin mRNA component also appeared to be present in the cells. Exposure of the cells to dimethylsulfoxide for 48 hours led to considerable increases in the rates of decay of all but the globin mRNA. The induction of erythroid differentiation caused by the drug appears to lead to activation of a mRNA-degradation process that affects individual species to different degrees. The newly synthesized actin and tubulin mRNAs lost their poly(A) rather rapidly. This was accompanied by accumulation of poly(A)-deficient mRNA chains, particularly in the case of actin mRNA. The steady-state distribution of mRNA components, determined by Northern blot analysis, also showed that the actin mRNA and one tubulin mRNA species have a high proportion of poly(A)-deficient molecules. The globin, P40 and P21 mRNAs showed little tendency to lose their poly(A) sequence. The steady-state globin and P40 mRNAs also had a low proportion of chains depleted of poly(A). For all five species, the proportions of poly(A)-deficient chains in newly synthesized mRNA were about the same in uninduced and induced cells, in spite of the large decreases in mRNA stability in the induced cells. The lack of correlation between tendency to lose poly(A) and rate of mRNA decay, and the large accumulation of poly(A)-deficient molecules in the cases of the actin and tubulin mRNAs suggest that the stability of mRNA is not determined solely by the presence of poly(A) on the RNA chains. The behavior of the untranslated species in induced and uninduced cells also fails to support the notion of a relationship between translation and mRNA decay.
在小鼠红白血病细胞中测定了几种信使核糖核酸（mRNA）的衰变率。肌动蛋白和微管蛋白mRNA的半衰期（t1/2）值分别为16至26小时和约7小时。珠蛋白mRNA以及另外两种受到翻译抑制的mRNA，即P40和P21 mRNA，其稳定性与核糖体RNA相当。细胞中似乎也存在一种稳定的微管蛋白mRNA成分。将细胞暴露于二甲基亚砜48小时导致除珠蛋白mRNA外所有mRNA的衰变率显著增加。该药物诱导的红细胞分化似乎导致了一个mRNA降解过程的激活，该过程对不同的mRNA种类影响程度不同。新合成的肌动蛋白和微管蛋白mRNA相当迅速地失去了它们的聚腺苷酸（poly(A)）。这伴随着缺乏poly(A)的mRNA链的积累，尤其是肌动蛋白mRNA的情况。通过Northern印迹分析确定的mRNA成分的稳态分布也表明，肌动蛋白mRNA和一种微管蛋白mRNA种类中缺乏poly(A)的分子比例很高。珠蛋白、P40和P21 mRNA几乎没有失去其poly(A)序列的趋势。稳态的珠蛋白和P40 mRNA中缺乏poly(A)的链的比例也很低。对于所有这五种mRNA种类，尽管诱导细胞中mRNA稳定性大幅下降，但新合成的mRNA中缺乏poly(A)的链的比例在未诱导和诱导细胞中大致相同。缺乏poly(A)的趋势与mRNA衰变率之间的相关性，以及肌动蛋白和微管蛋白mRNA中缺乏poly(A)的分子大量积累，表明mRNA的稳定性并非仅由RNA链上poly(A)的存在所决定。未翻译的mRNA种类在诱导和未诱导细胞中的行为也不支持翻译与mRNA衰变之间存在关联的观点。
