State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, Qingdao 266404, China.
Laboratory for Marine Drugs and Bioproducts, Qingdao Marine Science and Technology Center, Qingdao 266404, China.
Cells. 2024 Sep 11;13(18):1525. doi: 10.3390/cells13181525.
DNase II, identified in 1947 and named in 1953, is an acidic DNA endonuclease prevalent across organisms and crucial for normal growth. Despite its expression in nearly all human tissues, as well as its biological significance, DNase II's detailed functions and corresponding mechanisms remain unclear. Although many groups are trying to figure this out, progress is very limited. It is very hard to connect its indispensability with its DNA cleavage activity. In this study, we find that DNase II secreted to saliva can digest RNA in mildly acidic conditions, prompting us to hypothesize that salivary DNase II might digest RNA in the stomach. This finding is consistent with the interesting discovery reported in 1964 that RNA could inhibit DNase II's activity, which has been largely overlooked. This RNA digestion activity is further confirmed by using purified DNase II, showing activity to digest both DNA and RNA effectively. Here, we suggest redesignating DNase II as DNase II (RNase). The biological functions of DNase II are suggested to recycle intracellular RNA or digest external nucleic acids (both RNA and DNA) as nutrients. This discovery may untangle the mystery of DNase II and its significant biofunctions.
DNA 酶 II，于 1947 年被发现，1953 年被命名，是一种存在于生物体中的酸性 DNA 内切酶，对正常生长至关重要。尽管它在几乎所有人类组织中表达，并且具有重要的生物学意义，但 DNA 酶 II 的详细功能和相应的机制仍不清楚。尽管许多研究小组都在试图弄清楚这一点，但进展非常有限。很难将其不可或缺性与其 DNA 切割活性联系起来。在这项研究中，我们发现分泌到唾液中的 DNA 酶 II 可以在轻度酸性条件下消化 RNA，这促使我们假设唾液中的 DNA 酶 II 可能在胃中消化 RNA。这一发现与 1964 年报道的有趣发现一致，即 RNA 可以抑制 DNA 酶 II 的活性，但这一发现一直被忽视。这一 RNA 消化活性进一步通过使用纯化的 DNA 酶 II 得到证实，表明它可以有效地消化 DNA 和 RNA。在这里，我们建议重新命名 DNA 酶 II 为 DNA 酶 II（RNase）。DNA 酶 II 的生物学功能被认为是作为一种营养物质来回收细胞内的 RNA 或消化外部的核酸（包括 RNA 和 DNA）。这一发现可能会解开 DNA 酶 II 及其重要生物功能的谜团。
