Related Experiment Video

Updated: Jul 17, 2026

Intranuclear Microinjection of DNA into Dissociated Adult Mammalian Neurons
13:39

Intranuclear Microinjection of DNA into Dissociated Adult Mammalian Neurons

Published on: December 10, 2009

TOR-in(g) the nucleus

Chi Kwan Tsang1, X F Steven Zheng

  • 1Department of Pharmacology and Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.

Cell Cycle (Georgetown, Tex.)
|January 25, 2007
PubMed

Insights

The Target of rapamycin (TOR) protein moves between the cytoplasm and nucleus in yeast. Nuclear TOR is essential for regulating ribosomal DNA transcription, highlighting its multifaceted role in gene expression.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Yeast Genetics

Background:

  • The Target of rapamycin (TOR) pathway is a key regulator of eukaryotic cell growth.
  • TOR influences gene expression related to ribosome biogenesis, nutrient transport, and stress response.
  • Previously, TOR was primarily considered a cytoplasmic signaling kinase.

Purpose of the Study:

  • To investigate the subcellular localization and nuclear function of TOR in yeast.
  • To determine the role of TOR's nuclear localization in regulating transcription by different RNA polymerases.
  • To elucidate the multifaceted mechanisms by which TOR controls gene expression.

Main Methods:

  • Yeast genetics and molecular biology techniques.
  • Analysis of TOR protein localization using microscopy.
  • Assessment of RNA polymerase I and II dependent transcription in yeast mutants.

Main Results:

  • TOR dynamically shuttles between the cytoplasm and nucleus in yeast cells.
  • Nuclear localization and binding to the 35S ribosomal DNA (rDNA) promoter are critical for TOR's regulation of RNA polymerase I transcription.
  • TOR in either the cytoplasm or nucleus is sufficient for regulating RNA polymerase II-dependent transcription.

Conclusions:

  • TOR's nuclear localization is crucial for specific gene regulatory functions, particularly for rDNA transcription.
  • TOR employs distinct mechanisms to regulate transcription by RNA polymerase I and RNA polymerase II.
  • These findings reveal a more complex and multifaceted role for TOR in eukaryotic gene regulation, extending beyond its previously understood cytoplasmic functions.

More Related Videos

Mapping Absolute DNA Density in Cell Nuclei using Single-molecule Localization Microscopy10:57

Mapping Absolute DNA Density in Cell Nuclei using Single-molecule Localization Microscopy

Published on: November 11, 2025

Related Concept Videos

The Nucleus01:25

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression and precisely regulates the production of proteins within the cell. In contrast, the DNA inside the mitochondria and chloroplast only carries out functions that are specific to those organelles.
Arrangement of DNA within Nucleus
The regulation of gene expression inside the nucleus is dependent on many factors, including the DNA structure. The...
The Nucleus01:32

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression and precisely regulates the production of proteins within the cell. In contrast, the DNA inside the mitochondria and chloroplast only carries out functions that are specific to those organelles.
Arrangement of DNA within Nucleus
The regulation of gene expression inside the nucleus is dependent on many factors, including the DNA structure. The...
The Nucleus01:25

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression and precisely regulates the production of proteins within the cell. In contrast, the DNA inside the mitochondria and chloroplast only carries out functions that are specific to those organelles.
Arrangement of DNA within Nucleus
The regulation of gene expression inside the nucleus is dependent on many factors, including the DNA structure. The...
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,...
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,...
Directionality of Nuclear Transport01:42

Directionality of Nuclear Transport

Ras-related nuclear protein or Ran is a small G protein that cycles between its GTP and GDP bound states. Ran specific regulators, a Ran GTPase Activating Protein or RanGAP present in the cytosol and a Ran guanine nucleotide exchange factor or RanGEF present inside the nucleus regulate GTP/GDP exchange. A high concentration of GTP inside the cells, in addition to this asymmetric distribution of  Ran-specific regulators, leads to a higher RanGTP concentration inside the nucleus. This...