Protocol for effective surface passivation for single-molecule studies of chromatin and topoisomerase II.

For single-molecule studies requiring surface anchoring of biomolecules, poorly passivated surfaces can result in alterations of biomolecule structure and function that lead to artifacts. Here, we present a surface passivation assay for single-molecule studies of chromatin and topoisomerase II. We detail steps for preparing a nucleosome array and hydrophobic nitrocellulose-coated flow cell.

Tunable elliptical cylinders for rotational mechanical studies of single DNA molecules.

The angular optical trap (AOT) is a powerful technique for measuring the DNA topology and rotational mechanics of fundamental biological processes. Realizing the full potential of the AOT requires rapid torsional control of these processes. However, existing AOT quartz cylinders are limited in their ability to meet the high rotation rate requirement while minimizing laser-induced photodamage.

Orbital Trauma Epidemiologic Characteristics by Life Stage.

Study Design: Retrospective database review.

Objective: This study aims to characterize and compare the epidemiological factors of orbital trauma between life stages by utilizing the National Electronic Injury Surveillance System (NEISS), a nationally representative database.

Methods: The NEISS was queried for orbital injuries from 2013 to 2022.

Chromatin Buffers Torsional Stress During Transcription.

Transcription through chromatin under torsion represents a fundamental problem in biology. Pol II must overcome nucleosome obstacles and, because of the DNA helical structure, must also rotate relative to the DNA, generating torsional stress. However, there is a limited understanding of how Pol II transcribes through nucleosomes while supercoiling DNA.

Human Topoisomerase IIα Promotes Chromatin Condensation Via a Phase Transition.

Topoisomerase II (topo II) enzymes are essential enzymes known to resolve topological entanglements during DNA processing. Curiously, while yeast expresses a single topo II, humans express two topo II isozymes, topo IIα and topo IIβ, which share a similar catalytic domain but differ in their intrinsically disordered C-terminal domains (CTDs). During mitosis, topo IIα and condensin I constitute the most abundant chromosome scaffolding proteins essential for chromosome condensation.