Processive RNA polymerization and promoter recognition in an RNA World

Area of Science:

• Biochemistry
• Origin of Life Research
• Molecular Evolution

Background:

• Early life is hypothesized to depend on RNA self-replication by RNA replicases.
• The evolutionary pathways of these replicases and their role in gene expression are not well understood.

Purpose of the Study:

• To engineer and select a novel RNA polymerase ribozyme.
• To investigate its ability to recognize RNA promoter sequences and self-replicate.
• To explore its potential role in the origin of life and gene expression.

Main Methods:

• Engineering and selection of a holopolymerase ribozyme.
• Utilizing a sigma factor-like specificity primer for promoter recognition.
• Investigating the polymerase's ability to rearrange into a processive elongation form.
• Testing self-programming capabilities for selective polymerization.

Main Results:

• Successfully engineered a holopolymerase ribozyme with promoter recognition capabilities.
• Demonstrated selective polymerization based on RNA promoter sequences.
• The ribozyme can distinguish between different RNA promoters, defining "self" from "nonself."
• The polymerase exhibits a clamp-like mechanism potentially enabling strand invasion.

Conclusions:

• The engineered ribozyme provides a model for early RNA replicases.
• Selective promoter recognition is a key step in the evolution of self-replication and avoiding parasitic replicators.
• The clamp-like mechanism is a critical feature for RNA replication in early life.
• This work sheds light on the evolution of gene expression from RNA replicases.