Epigenetics is the study of how heritable changes in gene expression occur without changes in the DNA sequence itself. One important epigenetic mechanism involves the addition of chemical modifications called "methyl groups" to the DNA molecule. These modifications are catalyzed by enzymes called DNA methyltransferases (DNMTs).
DNMTs are multi-subunit complexes that contain several different proteins. The precise structure of these complexes and how they interact with DNA has been poorly understood. However, a recent study by researchers at the University of California, Los Angeles has now shed light on this important question.
Using a technique called cryo-electron microscopy, the researchers were able to obtain high-resolution images of the DNMT1 complex, which is responsible for maintaining DNA methylation patterns during cell division. The images revealed that the complex has a unique "hat" shape, with the methyltransferase domain located at the top of the complex.
This hat shape is important for the function of the DNMT1 complex. It allows the complex to bind to the DNA molecule and position the methyltransferase domain in the correct location to add methyl groups to the DNA.
The study also revealed that the DNMT1 complex interacts with several other proteins, including a regulatory protein called DNMT3L. This interaction is important for the proper targeting of the DNMT1 complex to specific regions of the DNA molecule.
The findings of this study provide important insights into the structure and function of DNMT1 complex, and how it contributes to epigenetic gene regulation. This information could lead to the development of new drugs that target DNMT1 and other epigenetic enzymes to treat diseases such as cancer and neurodegenerative disorders.
