Related Experiment Video

Updated: Aug 16, 2026

Aip1p Dynamics Are Altered by the R256H Mutation in Actin
08:57

Aip1p Dynamics Are Altered by the R256H Mutation in Actin

Published on: July 30, 2014

Altered subcellular distribution of nucleolar protein fibrillarin by actinomycin D in HEp-2 cells

Min Chen1, Ping Jiang

  • 1Research Center of Basic Medicine, School of Medicine, Jiangsu University, Zhenjiang 212001, China. chenmin_88@yahoo.com.cn

Acta Pharmacologica Sinica
|June 24, 2004
PubMed
Abstract

Insights

Actinomycin D disrupts the nucleolar protein fibrillarin

Area of Science:

  • Cell Biology
  • Molecular Biology

Background:

  • Fibrillarin is a key nucleolar protein essential for ribosome biogenesis.
  • Understanding fibrillarin's nucleolar maintenance is crucial for cellular function.

Purpose of the Study:

  • To investigate the impact of actinomycin D on fibrillarin's subcellular localization.
  • To elucidate the mechanisms governing fibrillarin's retention within the nucleolus.

Main Methods:

  • Indirect immunofluorescence assay to visualize fibrillarin distribution.
  • Immunoblotting to assess total cellular fibrillarin levels and integrity.

Main Results:

  • Actinomycin D treatment caused fibrillarin to translocate from nucleoli to nucleoplasm.
  • Total fibrillarin levels and integrity remained unchanged.
  • Dislocation was reversible at low actinomycin D concentrations but not at high concentrations.

Conclusions:

  • Actinomycin D induces fibrillarin redistribution in HEp-2 cells.
  • Active RNA synthesis is critical for maintaining fibrillarin within the nucleolus.

More Related Videos

In Vitro Polymerization of F-actin on Early Endosomes12:15

In Vitro Polymerization of F-actin on Early Endosomes

Published on: August 28, 2017

A Time-Efficient Fluorescence Spectroscopy-Based Assay for Evaluating Actin Polymerization Status in Rodent and Human Brain Tissues06:54

A Time-Efficient Fluorescence Spectroscopy-Based Assay for Evaluating Actin Polymerization Status in Rodent and Human Brain Tissues

Published on: June 3, 2021

Related Concept Videos

The Nucleolus02:55

The Nucleolus

The nucleolus is the most prominent substructure of the nucleus. When it was first discovered, it was considered to be an isolated organelle that forms fibrils and granules. In 1931, the relationship between the nucleolus and chromosomes was first described by Heitz. He observed that the appearance and size of nucleolus varies depending on the stage of the cell cycle. He also noticed constricted regions on different chromosomes clustered together at definite cell cycle stages. These regions,...
Generation of Straight or Branched Actin Filaments01:14

Generation of Straight or Branched Actin Filaments

The straight or branched structure formation of actin filaments is controlled by nucleating proteins such as the formins and Arp2/3 complex. Formin-mediated assembly results in straight filaments, whereas Arp2/3 protein complex-mediated assembly results in branched actin filaments.
Arp2/3 Complex
Arp2/3 complex is a seven-subunit complex consisting of two proteins similar to actin- Arp2 and Arp3, and five other subunits that help keep Arp2 and Arp3 inactive. When required, the complex is...
Actin Filament Depolymerization01:19

Actin Filament Depolymerization

Actin filaments (F-actin) are composed of actin subunits. The dissociation of actin monomers can occur from either end of F-actin. The rate of dissociation is faster from the minus-end or the pointed end, where the actin subunits exist with a bound ADP, together known as ADP-actin. The depolymerization of F-actin is aided by proteins, including the actin-depolymerizing factor (ADF) and cofilin family of proteins, gelsolin, and glia maturation factor (GMF).
In F-actin, the ADF/cofilin proteins...
Formation of Higher-order Actin Filaments01:11

Formation of Higher-order Actin Filaments

The polymerization of G-actin monomers into filamentous F-actin is a multi-step process. Once the F-actins are formed, they can bundle together in different arrangements to form higher-order networks and regulate cellular functions. Common examples include the formation of lamellipodia and filopodia at the cell's leading edge by actin reorganization in a migrating cell. The microvilli on the brush border epithelial cells are also formed through the F-actin network.
The high-order actin networks...
The Role of Actin and Myosin in Non-muscle Cells01:10

The Role of Actin and Myosin in Non-muscle Cells

Actin and myosin or actomyosin filaments also play a significant role in cells other than those involved in muscle contraction (which occurs within the sarcomere of muscle cells). The mechanism of non-muscle cell contractile bundles was first observed in Dictyostelium and Acanthamoeba. In non-muscle cells, two bundles are commonly found: stress fibers and actomyosin adherence belts. These contractile bundles are smaller and less organized than the ones found in muscle cells. They  are held...
Actin Polymerization and Cell Motility01:13

Actin Polymerization and Cell Motility

Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.