Gross M, Redman R
Biochim Biophys Acta. 1987 Feb 27;908(2):123-30. doi: 10.1016/0167-4781(87)90051-0.
We have examined the effect of the purified IgG from the serum of guinea pigs immunized with a highly purified preparation of rabbit reticulocyte, hemin-controlled translational repressor (HCR) on protein synthesis in the reticulocyte lysate. We have found that the anti-HCR (but not non-immune) IgG completely prevents or reverses the suppression of protein synthesis that occurs in hemin-deficient lysate, providing a direct and definitive demonstration that the inhibitory effect of hemin-deficiency is mediated solely by the activation of HCR. The anti-HCR IgG also prevents or reverses the phosphorylation of eIF-2 alpha and the reduced binding of Met-tRNAf to 40 S ribosomal subunits that accompanies the inhibition of protein synthesis in hemin-deficient lysate. In contrast, the anti-HCR IgG has no effect on the inhibition produced by low levels of double-stranded RNA (that is due to the activation of a separate protein kinase), but it does partly reverse inhibition due to oxidized glutathione, ethanol, and phosphatidylserine, indicating that the effect of these components is mediated, at least in part, by the activation of HCR. Finally, we have confirmed our earlier observation that an excess of proHCR, the inactive precursor of HCR, has little effect on the neutralization of HCR by limiting anti-HCR IgG, suggesting that the antigenic determinants on HCR are not exposed on ProHCR.
我们检测了用高度纯化的兔网织红细胞血红素控制的翻译阻遏物（HCR）制备物免疫的豚鼠血清中纯化IgG对网织红细胞裂解物中蛋白质合成的影响。我们发现，抗HCR（而非非免疫）IgG能完全阻止或逆转血红素缺乏裂解物中发生的蛋白质合成抑制，这直接且明确地证明了血红素缺乏的抑制作用仅由HCR的激活介导。抗HCR IgG还能阻止或逆转eIF-2α的磷酸化以及Met-tRNAf与40S核糖体亚基结合的减少，这些现象伴随血红素缺乏裂解物中蛋白质合成的抑制而出现。相比之下，抗HCR IgG对低水平双链RNA产生的抑制（这是由于另一种蛋白激酶的激活所致）没有影响，但它确实能部分逆转由氧化型谷胱甘肽、乙醇和磷脂酰丝氨酸引起的抑制，这表明这些成分的作用至少部分是由HCR的激活介导的。最后，我们证实了我们早期的观察结果，即过量的HCR前体（proHCR），即HCR的无活性前体，并不能通过限制抗HCR IgG来显著影响HCR的中和作用，这表明HCR上的抗原决定簇在proHCR上并未暴露。
