Mutagenesis Sensitivity Mapping of Human Enhancers In Vivo

Area of Science:

• Genetics
• Developmental Biology
• Genomics

Background:

• Distant-acting enhancers are crucial for human development.
• Understanding enhancer sequence function is vital for interpreting disease-causing mutations.

Purpose of the Study:

• To determine the functional sensitivity of human developmental enhancers to mutagenesis in vivo.
• To identify critical nucleotides and sequence features within enhancers.

Main Methods:

• Systematic mutagenesis of 12-basepair blocks in seven human developmental enhancers.
• Generation of over 1700 transgenic mice to assess enhancer activity in vivo.
• Application of predictive modeling and machine learning to annotate functional nucleotides.

Main Results:

• 69% of mutated blocks impaired normal in vivo enhancer activity.
• Mutations more frequently caused loss of function (60%) than gain of function (9%).
• Machine learning models accurately predicted functional motifs, identifying 59% of functional blocks.

Conclusions:

• Human enhancers possess a high density of sequence features essential for in vivo function.
• This research provides a foundational resource for understanding enhancer function and human development.