Hernandez N
EMBO J. 1985 Jul;4(7):1827-37. doi: 10.1002/j.1460-2075.1985.tb03857.x.
U1 is a small non-polyadenylated nuclear RNA that is transcribed by RNA polymerase II and is known to play a role in mRNA splicing. The mature 3' end of U1 snRNA is formed in at least two steps. The first step generates precursors of U1 RNA with a few extra nucleotides at the 3' end; in the second step, these precursors are shortened to mature U1 RNA. Here, I have determined the sequences required for the first step. Human U1 genes with various deletions and substitutions near the 3' end of the coding region were constructed and introduced into HeLa cells by DNA transfection. The structure of the RNA synthesized during transient expression of the exogenous U1 gene was analyzed by S1 mapping. The results show that a 13 nucleotide sequence located downstream from the U1 coding region and conserved among U1, U2 and U3 genes of different species is the only sequence required to direct the first step in the formation of the 3' end of U1 snRNA.
U1是一种由RNA聚合酶II转录的小型非聚腺苷酸化核RNA，已知其在mRNA剪接中发挥作用。U1 snRNA的成熟3'端至少通过两个步骤形成。第一步产生在3'端带有几个额外核苷酸的U1 RNA前体；在第二步中，这些前体被缩短为成熟的U1 RNA。在此，我确定了第一步所需的序列。构建了在编码区3'端附近具有各种缺失和替换的人U1基因，并通过DNA转染将其导入HeLa细胞。通过S1作图分析了外源U1基因瞬时表达期间合成的RNA的结构。结果表明，位于U1编码区下游且在不同物种的U1、U2和U3基因中保守的13个核苷酸序列是指导U1 snRNA 3'端形成第一步所需的唯一序列。
