NUCLEAR PROTEINS THAT BIND THE PREMESSENGER RNA 3' SPLICE-SITE SEQUENCE R(UUAG/G) AND THE HUMAN TELOMERIC DNA-SEQUENCE D(TTAGGG)N
NUCLEAR PROTEINS THAT BIND THE PREMESSENGER RNA 3' SPLICE-SITE SEQUENCE R(UUAG/G) AND THE HUMAN TELOMERIC DNA-SEQUENCE D(TTAGGG)N
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DOI：
10.1128/mcb.13.7.4301
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发表时间：
1993-07-01
影响因子：
5.3
通讯作者：
CECH, TR
中科院分区：
文献类型：
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作者：
ISHIKAWA, F;MATUNIS, MJ;CECH, TR
HeLa细胞核蛋白结合单链d（TTAGGG）n，人端粒DNA重复序列，确定和纯化的凝胶阻滞试验。免疫学数据和肽测序实验表明，纯化的蛋白质是相同的或密切相关的异质核核糖核蛋白（hnRNP）A1，A2-B1，D，和E和核仁素。这些蛋白质与具有r（UUAGGG）重复序列的RNA寡核苷酸的结合比与相同序列的DNA的结合更紧密。这种结合是序列特异性的，因为前4个碱基[r（UUAG）]中任何一个的点突变都消除了它。含有D和E hnRNP的部分显示出与具有人β-珠蛋白间插序列1的3'剪接位点序列的合成寡核糖核苷酸特异性结合，该序列包括序列UUAGG。通过二维凝胶电泳进一步鉴定该组分中的蛋白质为DO 1、D 02、D1* 和E0;有趣的是，hnRNP D和E组的这些成员是与hnRNP复合物不稳定相关的核蛋白。这些研究建立了这些D和E hnRNP的结合特异性。此外，他们提出了这些hnRNP可能与染色体端粒结合的可能性，除了在前mRNA代谢中发挥作用之外。
HeLa cell nuclear proteins that bind to single-stranded d(TTAGGG)n, the human telomeric DNA repeat, were identified and purified by a gel retardation assay. Immunological data and peptide sequencing experiments indicated that the purified proteins were identical or closely related to the heterogeneous nuclear ribonucleoproteins (hnRNPs) Al, A2-B1, D, and E and to nucleolin. These proteins bound to RNA oligonucleotides having r(UUAGGG) repeats more tightly than to DNA of the same sequence. The binding was sequence specific, as point mutation of any of the first 4 bases [r(UUAG)] abolished it. The fraction containing D and E hnRNPs was shown to bind specifically to a synthetic oligoribonucleotide having the 3' splice site sequence of the human beta-globin intervening sequence 1, which includes the sequence UUAGG. Proteins in this fraction were further identified by two-dimensional gel electrophoresis as DO1, D02, D1*, and E0; intrigttingly, these members of the hnRNP D and E groups are nuclear proteins that are not stably associated with hnRNP complexes. These studies establish the binding specificities of these D and E hnRNPs. Furthermore, they suggest the possibility that these hnRNPs could perhaps bind to chromosome telomeres, in addition to having a role in pre-mRNA metabolism.