ROLE OF CYTOSINE METHYLATION IN C. CINEREUS

检测胞嘧啶甲基化在鸡腿菇中的作用 已知CpG甲基化参与基因沉默，并被认为是 负责基因组印记和X染色体失活。这 研究工作解决了胞嘧啶甲基化在真菌中的后果 系统鸡腿菇和目前正在研究的位置和 色氨酸合成酶中5-甲基胞嘧啶(M5C)残基的含量 基因(Trpi)。基因组测序方案已被改进以研究 我们真菌系统中的甲基化。在这一关键反应中 方案，胞嘧啶在钠处理后脱氨基为尿嘧啶 亚硫酸盐，而M5C保持不变。因此，M5C的存在 残基由序列数据中剩余的胞嘧啶表示。 对六个同时具有Trp+和Trp-子代的四分体的分析使我能够 直接比较沉默的人甲基化的差异 和不沉默的基因。所有DNA的序列分析证明 胞嘧啶甲基化主要发生在CpG二核苷酸上，如 哺乳动物系统，并且Trp-DNA有更多的甲基化 胞嘧啶与色氨酸+DNA的比较。进一步的分析将确定 胞嘧啶甲基化有位点特异性，如果特异性的话 甲基化胞嘧啶是形成trp1的必要条件和充分条件。 基因不活跃。C.cinereus已被证明是一种研究的模式系统 甲基化，并可能为我们提供关于基因沉默是如何发生在 这一物种，可能作为一个整体存在于真核生物中。这可能会导致 更好地理解M5C在基因表达调控中的作用 并进一步阐明其在癌症等疾病中的作用。 脆性X综合征。

Examining the Role of Cytosine Methylation in Coprinus cinereus CpG methylation is known to be involved in gene silencing and to be responsible for genomic imprinting and X-chromosome inactivation. This work addresses the consequences of cytosine methylation in the fungal system Coprinus cinereus and currently is studying the location and extent of 5-methyl cytosine (m5C) residues in the tryptophan synthetase gene (trpi). The genomic sequencing protocol has been refined to study methylation in our fungal system. In the critical reaction of this protocol, cytosine is deaminated to uracil upon treatment with sodium bisulfite while m5C remains unchanged. Thus, the presence of m5C residues is indicated by the remaining cytosines in the sequence data. Analysis of six tetrads with both Trp+ and Trp- progeny allowed me to make a direct comparison of differences in methylation between silenced and unsilenced genes. Sequence analysis of all DNAs proved that cytosine methylation occurs mostly at the CpG dinucleotide as in mammalian systems, and that Trp- DNA has a larger amount of methylated cytosines as compared to Trp+ DNA. Further analysis will determine if there is site specificity for cytosine methylation and if specific methylated cytosines are necessary and sufficient to render the trp1 gene inactive. C. cinereus has proven to be a model system for studying methylation and may give us clues about how gene silencing occurs in this species and possibly in eukaryotes as a whole. This may lead to a better understanding of the role of m5C in controlling gene expression and further elucidate its role in diseases such as cancer and the Fragile-X syndrome.