DNA moves steadily through interphase, providing cells with a robust housekeeping system

DNA moves steadily through interphase, providing cells with a robust housekeeping system

The swaying motion of chromatin maintains a steady state during interphase despite increases in the amount of DNA and nucleolar size. Credit: Shiori Iida & Kazuhiro Maeshima, National Institute of Genetics, ROIS

Researchers in Japan have discovered that the local movement of DNA inside human cells remains constant throughout interphase, as the cell grows and copies its own DNA for cell division. The study indicates that steady-state movement of DNA allows cells to perform housekeeping tasks in similar environments during interphase.

The team, led by Professor Kazuhiro Maishima of the National Institute of Genetics, ROIS, published their findings on June 3 in science progress.

To fit inside the cell nucleus, DNA is organized into chromatin, in which strands of DNA are wrapped around clusters of histone proteins, filament-like around a spool, to form structures known as nucleosomes. The nucleosomes can then be folded into more compact structures and formed as chromatin. Previous research shows that chromatin is constantly oscillating in living cells.

Such as cell cycle It progresses (i.e., G1, S and G2 stages), as the genomic DNA replicates and the nucleolus becomes larger, the nuclear environment surrounding chromatin changes dramatically. Mashima and colleagues at the National Institute of Genetics in Mishima, Japan posed this question: How does chromatin behavior change during interphase?

Maeshima’s group used high-resolution optical microscopy technology to look at the behavior of single nucleosomes inside living cells for a very short time, about one second.

The oscillating motion of individual nucleosomes (white dots) between the G1 (left) and G2 (right) phases is similar. Credit: Shiori Iida & Kazuhiro Maeshima, National Institute of Genetics, ROIS

Maeshima and colleagues revealed that local chromatin movement remains constant throughout interphase, despite genome DNA duplication by DNA replication and nucleolar growth. The researchers also showed that nuclear growth without replication does not affect the steady-state movement of chromatin. Thus, local chromatin movement is independent of such nuclear changes during interphase.

“This is an important finding because steady-state movement allows cells to perform their routine actions, such as RNA transcription and DNA replication, under similar nuclear environments,” said first author Shiuri Lida. “Local chromatin movement can control the accessibility of genomic DNA to search for a target or to recruit a piece of machinery. Steady-state movement of chromatin provides a robust cellular system in which DNA functions are not affected by various nuclear changes.”

Cells can change Chromatin movement from the steady state to perform their assigned functions in response to DNA damage, among many other tasks,” Mashima said. He and his team aim to further explore how a movement regulator, the proteins that are involved in the process of regulation, and how DNA behaves during it cell division. “Our ultimate goal is to understand how human genomic DNA behaves inside the cell for reading genetic information Mashima said.

Study suggests gene transcription machinery constrains DNA movements

more information:
Shiori Iida et al, Single nuclear imaging reveals steady-state movement of interphase chromatin in living human cells, science progress (2022). DOI: 10.1126 / sciadv.abn5626. www.science.org/doi/10.1126/sciadv.abn5626

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