Williams A S, Marzluff W F
Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill 27599.
Nucleic Acids Res. 1995 Feb 25;23(4):654-62. doi: 10.1093/nar/23.4.654.
Complexes of different electrophoretic mobility containing the stem-loop binding protein, a 45 kDa protein, bound to the stem-loop at the 3' end of histone mRNA, are present in both nuclear and cytoplasmic extracts from mammalian cells. We have determined the effect of changes in the loop, in the stem and in the flanking sequences on the affinity of the SLBP for the 3' end of histone mRNA. The sequence of the stem is particularly critical for SLBP binding. Specific sequences both 5' and 3' of the stem-loop are also required for high-affinity binding. Expanding the four base loop by one or two uridines reduced but did not abolish SLBP binding. RNA footprinting experiments show that the flanking sequences on both sides of the stem-loop are critical for efficient binding, but that cleavages in the loop do not abolish binding. Thus all three regions of the RNA sequence contribute to SLBP binding, suggesting that the 26 nt at the 3' end of histone mRNA forms a defined tertiary structure recognized by the SLBP.
含有茎环结合蛋白（一种45 kDa的蛋白质）且与组蛋白mRNA 3'端的茎环相结合的不同电泳迁移率复合物，存在于哺乳动物细胞的核提取物和细胞质提取物中。我们已经确定了环、茎以及侧翼序列的变化对茎环结合蛋白（SLBP）与组蛋白mRNA 3'端亲和力的影响。茎的序列对于SLBP结合尤为关键。茎环5'和3'端的特定序列对于高亲和力结合也是必需的。将四碱基环扩展一个或两个尿苷会降低但不会消除SLBP结合。RNA足迹实验表明，茎环两侧的侧翼序列对于有效结合至关重要，但环中的切割不会消除结合。因此，RNA序列的所有三个区域都有助于SLBP结合，这表明组蛋白mRNA 3'端的26个核苷酸形成了一种被SLBP识别的特定三级结构。
