The mechanistic role of METTL14 in UVB-induced skin tumorigenesis

核苷酸切除修复（NER）是DNA修复的主要机制，它可以清除大体积的DNA损伤 产品所造成的UVB辐射以及其他环境致癌物质。作为canonical的子类型 NER，全球基因组NER（GG-NER）修复整个基因组的DNA损伤，并且对于 预防皮肤癌，美国最常见的癌症，以及大脑和肺部的癌症1-7。 然而，调节GG-NER能力的分子机制仍然知之甚少。最近我们 发现了胃L14（甲基转移酶样14）的新作用，作为N6- 甲基腺苷（m6 A）RNA甲基转移酶和受体，促进GG-NER和抑制肿瘤 增长m6 A RNA甲基化是真核生物信使RNA中最丰富的内部化学修饰， RNA（mRNA）以及长非编码RNA（lncRNA）。m6 A修饰调节RNA及其受体的命运 功能，如mRNA的稳定性，核加工，运输，定位，翻译，初级microRNA 加工和RNA-蛋白质相互作用。本提案的目标是确定 胃L14作为一个关键的m6 A作家，调节GG-NER和UVB诱导的皮肤癌。我们的初步数据 提示胃L14作为一种关键m6 A写入蛋白，在调节GG-NER和皮肤中起关键作用 肿瘤发生因此，我们假设，作为关键m6 A写入者的胃L14在GG-NER中起关键作用， UVB通过转录后调节其重要靶基因的表达诱导皮肤癌。 为了验证这一假设，我们将采用几种新的方法，包括转录组范围的m6 A作图， eCLIP-seq和RIP-seq。此外，我们将使用具有皮肤特异性胃L14缺失的新小鼠模型。我们 假设将在三个具体目标中进行检验。目的1将确定胃L14 调节GG-NER。目的2探讨UVB辐射下调胃L14的机制。 目的3将确定在UVB诱导的小鼠皮肤肿瘤发生中抑制胃L14的后果。 成功完成我们拟议的项目可能会极大地扩大我们对GG-NER法规的了解， 通过胃L14和m6 A RNA甲基化抑制肿瘤，为开发更好的 通过靶向胃L14通路预防和治疗皮肤癌的策略。癌症更多发生在皮肤上 比其他任何器官部位都多，很可能是由于环境破坏。此外，我们在GG-NER的工作 METLL 14不仅在皮肤癌中有重要意义，而且也适用于其他肿瘤类型。

Nucleotide excision repair (NER) is the major DNA repair mechanism that removes bulky DNA damage products caused by UVB radiation as well as other environmental carcinogens. As a subtype of canonical NER, global genome NER (GG-NER) repairs DNA damage across the whole genome, and is essential for preventing skin cancer, the most common cancer in the US, as well as cancers in the brain and lungs 1-7. However, the molecular mechanism of regulating GG-NER capacity remains poorly understood. Recently, we discovered a novel role for METTL14 (methyltransferase-like 14), as a key component of the N6- methyladenosine (m6A) RNA methyltransferase and writer, in promoting GG-NER and suppressing tumor growth. m6A RNA methylation is the most abundant internal chemical modification in eukaryotic messenger RNA (mRNA) as well as long non-coding RNA (lncRNA). m6A modification regulates the fate of RNA and its functions, such as mRNA stability, nuclear processing, transport, localization, translation, primary microRNA processing, and RNA-protein interactions. The goal of this proposal is to determine the mechanism by which METTL14, as a key m6A writer, regulates GG-NER and UVB-induced skin cancer. Our preliminary data suggest that METTL14, as a key m6A writer protein, plays a critical role in regulating GG-NER and skin tumorigenesis. Thus we hypothesize that METTL14, as a key m6A writer, plays a critical role in GG-NER and UVB-induced skin cancer through posttranscriptionally regulating the expression of its essential target genes. To test this hypothesis, we will employ several new methods including transcriptome-wide m6A mapping, eCLIP-seq, and RIP-seq. In addition, we will use a new mouse model with skin-specific METTL14 deletion. Our hypothesis will be tested in three Specific Aims. Aim 1 will determine the mechanism by which METTL14 regulates GG-NER. Aim 2 will determine the mechanism by which UVB radiation down-regulates METTL14. Aim 3 will determine the consequences of METTL14 inhibition in UVB-induced skin tumorigenesis in mice. Successful completion of our proposed project may vastly expand our knowledge of GG-NER regulation and tumor suppression by METTL14 and m6A RNA methylation, providing new opportunities for developing better strategies to prevent and treat skin cancer by targeting the METTL14 pathway. Caners arise in the skin more than in any other organ site, most likely due to environmental damage. In addition, our work here in GG-NER and METLL14 is not only significant in skin cancer, but is also applicable to other tumor types as well.