ARE VERTEBRATE EXONS SCANNED DURING SPLICE-SITE SELECTION
ARE VERTEBRATE EXONS SCANNED DURING SPLICE-SITE SELECTION
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DOI：
10.1038/360277a0
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发表时间：
1992-11-19
期刊：
影响因子：
64.8
通讯作者：
BERGET, SM
中科院分区：
文献类型：
--
作者：
NIWA, M;MACDONALD, CC;BERGET, SM
作为扫描机制的结果，剪接位点的配对识别是解释脊椎动物剪接协调的一个有吸引力的模型1。这种机制将预测在扫描单元中的位点极性识别，但没有证据表明内含子之间存在极性梯度2 -4。我们已经提出，外显子而不是内含子是脊椎动物中的识别单位5，并且多聚腺苷酸化和剪接因子在3 '末端外显子的识别过程中相互作用6 -8。相互作用反映在体外聚腺苷酸化的最大速率中。如果在这种相互作用期间扫描整个外显子，则插入5'剪接位点应抑制聚腺苷酸化。在这里，我们报告在体外和体内的5'剪接位点位于3'-末端外显子的识别，以及伴随的多聚腺苷酸化和紫外线交联的多聚腺苷酸化因子的抑郁症。仅当3'和5'剪接位点彼此在300个核苷酸内时才发现交联减少。这些结果与剪接位点选择的外显子扫描机制是一致的。
PAIRWISE recognition of splice sites as a result of a scanning mechanism is an attractive model to explain the coordination of vertebrate splicing1. Such a mechanism would predict a polarity-of-site recognition in the scanned unit, but no evidence for a polarity gradient across introns has been found2-4. We have suggested that the exon rather than the intron is the unit of recognition in vertebrates5 and that polyadenylation and splicing factors interact during recognition of 3'-terminal exons6-8. Interaction is reflected in maximal rates of in vitro polyadenylation. If scanning across the exon is operating during this interaction, then insertion of a 5' splice site should depress polyadenylation. Here we report recognition in vitro and in vivo of a 5' splice site situated within a 3'-terminal exon, and a concomitant depression of polyadenylation and ultraviolet crosslinking of a polyadenylation factor. Decreased crosslinking was only found when the 3' and 5' splice sites were within 300 nucleotides of each other. These results are consistent with an exon scanning mechanism for splice-site selection.