Spores of Gram-positive bacteria contain 10s–1000s of different mRNAs. However, Bacillus subtilis spores contain only ∼ 50 mRNAs at > 1 molecule/spore, almost all transcribed only in the developing spore and encoding spore proteins. However, some spore mRNAs could be stabilized to ensure they are intact in dormant spores, perhaps to direct synthesis of proteins essential for spores’ conversion to a growing cell in germinated spore outgrowth. Recent work shows that some growing B. subtilis cell mRNAs contain a 5′-NAD cap. Since this cap may stabilize mRNA in vivo, its presence on spore mRNAs would suggest that maintaining some intact spore mRNAs is important, perhaps because they have a translational role in outgrowth. However, significant levels of only a few abundant spore mRNAs had a 5′-NAD cap, and these were not the most stable spore mRNAs and had likely been fragmented. Even higher levels of 5′-NAD-capping were found on a few low abundance spore mRNAs, but these mRNAs were present in only small percentages of spores, and had again been fragmented. The new data are thus consistent with spore mRNAs serving only as a reservoir of ribonucleotides in outgrowth.

中文翻译：

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枯草芽孢杆菌休眠孢子中mRNA的5'-NAD上限分析。

革兰氏阳性细菌的孢子含有10s–1000s的不同mRNA。然而，枯草芽孢杆菌的孢子在> 1个分子/孢子中仅含有约50个mRNA，几乎所有的mRNA仅在发育中的孢子中转录并编码孢子蛋白。但是，可以稳定某些孢子的mRNA，以确保它们在休眠的孢子中是完整的，也许可以指导合成合成，这些蛋白对于在发芽的孢子生长中的孢子转化为生长的细胞至关重要。最近的工作表明，一些正在生长的枯草芽孢杆菌细胞mRNA含有5'-NAD帽。由于该帽可能在体内稳定mRNA，它在孢子mRNA上的存在表明维持一些完整的孢子mRNA很重要，也许是因为它们在生长中具有翻译作用。然而，只有少数丰富的孢子mRNA的显着水平具有5'-NAD帽，并且这些不是最稳定的孢子mRNA，并且可能被片段化。在一些低丰度的孢子mRNA上发现了更高水平的5'-NAD帽，但这些mRNA仅以小比例的孢子存在，并再次被片段化。因此，新数据与孢子mRNA一致，孢子mRNA仅作为产物中的核糖核苷酸贮库。