Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Saturday Speaker Abstracts

The Replisome Undergoes Multiple Rounds of Disassembly and Restart Every Cell Cycle

Paul Wiggins

1,2,3

University of Washington, Seattle, WA, USA,

University of Washington, Seattle, WA,

USA,

University of Washington, Seattle, WA, USA.

The canonical model of replication describes a highly-processive and largely continuous process

in which the genome is duplicated. This continuous model is based upon in vitro reconstitution

and in vivo ensemble experiments. In this study, we characterize the replisome-complex

stoichiometry and dynamics with single-molecule resolution in bacterial cells. These

experiments reveal that the complex undergoes pervasive disassembly and reassembly every cell

cycle (>5 times). Strikingly, a significant fraction of cells (>40%) have only a single helicase and

polymerase complex. Many of the observed complexes have short lifetimes (<5 minutes). This

instability is conflict-induced: transcription inhibition stabilizes these complexes and increases

the replication rate. In contrast to the canonical model, DNA replication is a largely

discontinuous process in vivo as a consequence of frequent replication-transcription conflicts.

Protein Dynamics in Single Cells Unveil Regulatory and Therapeutic Principles

Sheng-Hong Chen

Academia Sinica, Taipei, Taiwan

No Abstract