SYNTHETIC PEPTIDES AS NUCLEAR-LOCALIZATION SIGNALS
SYNTHETIC PEPTIDES AS NUCLEAR-LOCALIZATION SIGNALS
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DOI：
10.1038/322641a0
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发表时间：
1986-08-14
期刊：
影响因子：
64.8
通讯作者：
KORNBERG, RD
中科院分区：
文献类型：
--
作者：
GOLDFARB, DS;GARIEPY, J;KORNBERG, RD
核包膜定义了一个隔间边界，该边界被穿透的气孔所穿透，这些气孔介导了一个显着的运输过程。前体RNA保留在细胞核内，而加工后的信使RNA1、转移RNA2和核糖体亚单位3被运输到细胞质。去往细胞核的蛋白质在合成后不久就会定位，有丝分裂后又会定位，而细胞质蛋白质则被排除在外。这个过程是高度特异的：脊椎动物启动子tRNAMet(TRNAimet)中的单个碱基变化使出口速度减少20倍5；猿猴病毒40(SV40)大T抗原中的一个点突变，将Lys 128转换为Thr(参考文献。6)或ASN(参阅7)，防止进口。Lys 128位于一个短的‘信号’序列中，当它与大的非核蛋白融合时，导致它们聚集在核6-8。其他真核蛋白的区域似乎也含有核定位信号，尽管还没有出现单一的共同序列9-13。本文报道了含有10个大T抗原序列残基的合成肽在与牛血清白蛋白(BSA)或免疫球蛋白G(IgG)交联时作为核定位信号，并显微注射到Xenopus卵母细胞中。用苏氨酸取代该多肽中赖氨酸128的位置，使其效力降低6-7倍。多肽连接的BSA的摄取是饱和的，并且游离肽的共同注射降低了摄取速度。这些发现表明了受体介导的摄取过程。通过使用抗肽抗体，在含有大T抗原样序列的人淋巴细胞的胞核提取液中发现了一组蛋白质，而不是胞浆提取液。
The nuclear envelope defines a compartment boundary which is penetrated by pores that mediate a remarkable transport process. Precursor RNAs are retained in the nucleus, while processed messenger RNA1, transfer RNA2and ribosomal subunits3are transported to the cytoplasm. Proteins destined for the nucleus become localized soon after synthesis and again following mitosis, while cytoplasmic proteins are excluded4. The process is highly specific: a single base change in vertebrate initiator tRNAMet(tRNAimet) reduces the rate of export 20-fold5; a point mutation within the simian virus 40 (SV40) large-T antigen, converting Lys 128 to Thr (ref. 6) or Asn (ref. 7), prevents import. Lys 128 lies within a short ‘signal’ sequence which, when fused to large non-nuclear proteins, causes their accumulation in nuclei6–8. Regions of other eukaryotic proteins also seem to contain nuclear localization signals, although a single consensus sequence has not emerged9–13. We report here that a synthetic peptide containing 10 residues of large-T antigen sequence serves as a nuclear localization signal when cross-linked to bovine serum albumin (BSA) or immunoglobulin G (IgG) and microinjected inXenopusoocytes. Substitution of Thr at the position of Lys 128 in this peptide renders it six- to sevenfold less effective. The uptake of peptide-linked BSA is saturable, and the rate is diminished by co-injection of free peptide. These findings are indicative of a receptor-mediated uptake process. With the use of anti-peptide antibodies, a family of proteins is revealed in nuclear but not cytoplasmic extracts of human lymphocytes which contain large-T antigen-like sequences.