The invention relates to the identification of genetic signatures and expression profiles that are a part of the Base Excision Repair (BER) pathway, a major DNA repair pathway that modifies base lesions. In one embodiment, the present invention provides a method of determining responsiveness of treatment by BER inhibitors for malignant glioma by determining the presence of a low level of expression of Apex 1, a low level of expression of Apex 2, and a high level of expression of MPG.

The invention relates to the identification of genetic signatures and expression profiles that are a part of the Base Excision Repair (BER) pathway, a major DNA repair pathway that modifies base lesions. In one embodiment, the present invention provides a method of determining responsiveness of treatment by BER inhibitors for malignant glioma by determining the presence of a low level of expression of Apex 1, a low level of expression of Apex 2, and a high level of expression of MPG.

The invention relates to the identification of genetic signatures and expression profiles that are a part of the Base Excision Repair (BER) pathway, a major DNA repair pathway that modifies base lesions. In one embodiment, the present invention provides a method of determining responsiveness of treatment by BER inhibitors for malignant glioma by determining the presence of a low level of expression of Apex 1, a low level of expression of Apex 2, and a high level of expression of MPG.

A base editing system for achieving A-to-C and/or A-to-T base mutations and a use thereof are provided. A base editor is constructed by means of fusing 3-methyladenine DNA glycosylase with adenosine deaminase and Cas9 nuclease with impaired catalytic activity, which achieves adenine-based transversion for the first time. It is found through experimental comparison that AXBE, which is constructed by means of fusing mouse-derived 3-methyladenine DNA glycosylase with adenosine deaminase TadA-8e derived from E. coli and Cas9 nickase with impaired catalytic activity derived from Streptococcus pyogenes, has the best effect of catalyzing the transversion of adenine. The use of the base editing system in the gene therapy, cell therapy, human disease model production, and crop genetic breeding, etc. is promoted.

Provided is a programmable adenine base editor and system comprising the same and method of using the same. Also provided are MPG and mutants thereof, which can be used in the programmable adenine base editor.