Expansion and transformation of the minor spliceosomal system in the slime mold Physarum polycephalum
Expansion and transformation of the minor spliceosomal system in the slime mold Physarum polycephalum
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DOI：
10.1016/j.cub.2021.04.050
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发表时间：
2021-07-26
期刊：
影响因子：
9.2
通讯作者：
Roy, Scott W.
中科院分区：
文献类型：
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作者：
Larue, Graham E.;Elias, Marek;Roy, Scott W.
剪接体内含子中断核基因，并通过称为剪接体的机制从RNA转录物中移除（“剪接”）。虽然绝大多数剪接体内含子被所谓的主要剪接体（或“U2”）去除，但不同的真核生物也含有罕见的第二种形式，次要剪接体（“U12”）和相关的（“U12型”）内含子。(1-3)在所有已鉴定的物种中，U12型内含子以几个特征区分，包括在基因组中罕见（类似于所有内含子的0.5%），（4-6）含有扩展的进化上保守的剪接基序，（4，5，7，8）通常是古老的，（9，10）并且是低效剪接的。（11-13）在这里，我们报告了黏菌多头绒泡菌中的一个显著例外。Polycephalum基因组包含超过20，000个U12型内含子-比任何其他物种多25倍-富含多种非典型剪接边界以及转化的剪接信号，这些信号似乎与剪接体共同进化，这是由于大量获得有效剪接的U12型内含子。这些结果揭示了未成年人spliceosomal内含子和spliceosomal内含子一般的动力。
Spliceosomal introns interrupt nuclear genes and are removed from RNA transcripts ("spliced'') by machinery called spliceosomes. Although the vast majority of spliceosomal introns are removed by the so-called major (or "U2'') spliceosome, diverse eukaryotes also contain a rare second form, the minor ("U12'') spliceosome, and associated ("U12-type'') introns.(1-3) In all characterized species, U12-type introns are distinguished by several features, including being rare in the genome (similar to 0.5% of all introns),(4-6) containing extended evolutionarily conserved splicing motifs,(4,5,7,8) being generally ancient,(9,10) and being inefficiently spliced.(11-13) Here, we report a remarkable exception in the slime mold Physarum polycephalum. The P. polycephalum genome contains >20,000 U12-type introns-25 times more than any other species-enriched in a diversity of non-canonical splice boundaries as well as transformed splicing signals that appear to have co-evolved with the spliceosome due to massive gain of efficiently spliced U12-type introns. These results reveal an unappreciated dynamism of minor spliceosomal introns and spliceosomal introns in general.