N6-Methyl-dATP, as a base-modified ribonucleoside triphosphate, can act as an effective agonist for P2Y purinergic receptors in organisms such as guinea pigs and tapeworms[1]. N6-Methyl-dATP has also been demonstrated to play a critical role in carcinogenesis and stem cell fate determination[2].
In vitro, when HeLa cells are treated with 4μM N6-Methyl-dATP for 45 minutes, N6-methyladenine (N6-mA) must first be taken up by the cells and metabolized into the active form N6-Methyl-dATP to serve as a substrate for DNA polymerase and be integrated into DNA. This process falls under the category of RNA methylation products erroneously intervening in DNA synthesis through the nucleotide salvage pathway, and its integration mechanism relies on the non-specific recognition of modified nucleotides by DNA polymerase[3].
In vivo, microinjection of 0.3 mM N6-Methyl-dATP into homozygous MTH1KO zebrafish with knockout of the mth1 gene reveals that N6-Methyl-dATP present in the nucleotide pool can be incorporated into DNA, and this process can be blocked by the MTH1 protein[4]. In Arabidopsis MAPDA mutants, a high ratio of N6-Methyl-dATP/ATP (1.49%) induces root growth defects due to erroneous integration by RNA polymerase II or interference with energy metabolism[5].
References:
[1] He ML, Koshimizu TA, Tomić M, et al. Purinergic P2X(2) receptor desensitization depends on coupling between ectodomain and C-terminal domain. Mol Pharmacol 2002, 62(5):1187-1197.
[2] Pacini CE, Bradshaw CR, Garrett NJ, et al. Characteristics and homogeneity of N6-methylation in human genomes. Sci Rep 2019, 9(1):5185.
[3] Musheev MU, Baumgärtner A, Krebs L, et al. The origin of genomic N6-methyl-deoxyadenosine in mammalian cells. Nature Chemical Biology 2020, 16(6):630-634.
[4] Scaletti ER, Vallin KS, Bräutigam L, et al. MutT homologue 1 (MTH1) removes N6-methyl-dATP from the dNTP pool. J Biol Chem 2020, 295(15):4761-4772.
[5] Chen M, Urs MJ, Sánchez-González I, et al. m(6)A RNA Degradation Products Are Catabolized by an Evolutionarily Conserved N(6)-Methyl-AMP Deaminase in Plant and Mammalian Cells. Plant Cell 2018, 30(7):1511-1522.
N6-Methyl-dATP作为一种碱基修饰的核糖核苷三磷酸，在豚鼠、大肠绦虫等生物体内可作为P2Y 嘌呤受体的有效激动剂[1]。N6-Methyl-dATP也被证明在致癌作用和干细胞命运的决定中扮演关键角色[2]。
在体外，N6-Methyl-dATP（4μM）处理HeLa细胞45 min，N6-甲基腺嘌呤（N6-mA）需先被细胞摄取并代谢为活性形式N6-Methyl-dATP，方可作为DNA聚合酶的底物整合至DNA中。这一过程属于 RNA甲基化产物通过核苷酸补救途径错误介入DNA合成的范畴，其整合机制依赖于DNA聚合酶对修饰核苷酸的非特异性识别 [3]。
在体内，N6-Methyl-dATP（0.3mM）通过显微注射至mth1基因敲除的纯合子MTH1KO斑马鱼中，发现核苷酸库中存在的N6-Methyl-dATP能够掺入DNA中，而这一过程可被MTH1蛋白阻止[4]。在拟南芥MAPDA突变体中，高比率的N6-Methyl-dATP/ATP（1.49%）诱导RNA聚合酶II错误整合或能量代谢干扰导致根系生长缺陷[5]。