Williams A S, Ingledue T C, Kay B K, Marzluff W F
Program in Molecular Biology and Biotechnology, University of North Carolina, Chapel Hill 27599.
Nucleic Acids Res. 1994 Nov 11;22(22):4660-6. doi: 10.1093/nar/22.22.4660.
The stem-loop structure at the 3' end of replication-dependent histone mRNA is required for efficient pre-mRNA processing, localization of histone mRNA to the polyribosomes, and regulation of histone mRNA degradation. A protein, the stem-loop binding protein (SLBP), binds the 3' end of histone mRNA and is thought to mediate some or all of these processes. A mutant histone mRNA with two nucleotide changes in the loop was constructed and found to be transported inefficiently to the cytoplasm. The mutant histone mRNA, unlike the wild-type histone mRNA, was not rapidly degraded when DNA synthesis is inhibited, and was not stabilized upon inhibition of protein synthesis. The stem-loop binding protein (SLBP) has between a 20-50 fold greater affinity for the wild type histone stem-loop structure than for the mutant stem-loop structure, suggesting that the alteration in the efficiency of transport and the normal degradation pathway in histone mRNA may be due to the reduced affinity of the mutant stem-loop for the SLBP.
复制依赖型组蛋白mRNA 3'端的茎环结构对于高效的前体mRNA加工、组蛋白mRNA定位于多核糖体以及组蛋白mRNA降解的调控是必需的。一种名为茎环结合蛋白（SLBP）的蛋白质与组蛋白mRNA的3'端结合，并被认为介导了这些过程中的部分或全部。构建了一种在环区有两个核苷酸变化的突变组蛋白mRNA，发现其向细胞质的转运效率低下。与野生型组蛋白mRNA不同，当DNA合成受到抑制时，突变组蛋白mRNA不会迅速降解，并且在蛋白质合成受到抑制时也不会稳定。茎环结合蛋白（SLBP）对野生型组蛋白茎环结构的亲和力比对突变型茎环结构的亲和力高20至50倍，这表明组蛋白mRNA转运效率和正常降解途径的改变可能是由于突变茎环对SLBP的亲和力降低所致。
