Blastocladiella emersonii is an aquatic fungus of the phylum Blastocladiomycota, localized near the base of the fungal tree. Previous studies have shown that B. emersonii responds to heat shock and cadmium exposure inducing the transcription of a high number of genes. EST sequencing from heat shocked and cadmium exposed B. emersonii cells has shown that exposure to cadmium causes strong splicing inhibition. Despite the knowledge about splicing inhibition by cadmium, it is still unclear if other metal contaminants can cause the same response. In the present study, we have demonstrated that the effect of cadmium exposure on splicing inhibition is much stronger than that of other divalent metals such as cobalt and manganese. Data presented here also indicate that intron retention occurs randomly among the fungal transcripts, as verified by analyzing differently affected transcripts. In addition, we identified in the genome of B. emersonii the genes encoding the snRNA splicing components U1, U2, U4, U5 and U6 and observed that spliceosome snRNAs are upregulated in the presence of metals, in particular snRNA U1 in cells under cadmium exposure. This observation suggests that snRNA upregulation might be a defense of the fungal cell against the metal stress condition.

中文翻译：

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Blastocladiella emersonii 剪接体受到金属镉、钴和锰引起的剪接抑制的调节

Blastocladiella emersonii 是芽生菌门的一种水生真菌，位于真菌树的基部附近。以前的研究表明，B. emersonii 对热休克和镉暴露有反应，诱导大量基因的转录。来自热休克和镉暴露的 B. emersonii 细胞的 EST 测序表明，暴露于镉会导致强烈的剪接抑制。尽管了解镉对剪接的抑制作用，但仍不清楚其他金属污染物是否会引起相同的反应。在本研究中，我们已经证明镉暴露对剪接抑制的影响比其他二价金属（如钴和锰）强得多。这里提供的数据还表明内含子保留在真菌转录物中随机发生，通过分析不同影响的转录本来验证。此外，我们在 B. emersonii 的基因组中鉴定了编码 snRNA 剪接成分 U1、U2、U4、U5 和 U6 的基因，并观察到在金属存在下剪接体 snRNAs 上调，特别是在镉暴露下细胞中的 snRNA U1 . 这一观察结果表明，snRNA 上调可能是真菌细胞抵抗金属应激条件的一种防御措施。