Related Experiment Video

Updated: Jul 5, 2026

A Reporter Assay to Analyze Intronic microRNA Maturation in Mammalian Cells
06:48

A Reporter Assay to Analyze Intronic microRNA Maturation in Mammalian Cells

Published on: June 16, 2022

MicroRNA-155 suppresses activation-induced cytidine deaminase-mediated Myc-Igh translocation

Yair Dorsett1, Kevin M McBride, Mila Jankovic

  • 1Laboratory of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA.

Immunity
|May 6, 2008
PubMed

Insights

MicroRNA-155 (miR-155) acts as a tumor suppressor by regulating activation-induced cytidine deaminase (AID). This microRNA reduces potentially oncogenic translocations in vivo, highlighting its role in preventing cancer.

Area of Science:

  • Molecular Biology
  • Immunology
  • Genetics

Background:

  • MicroRNAs (miRNAs) are small noncoding RNAs regulating gene expression through target sequences.
  • Activation-induced cytidine deaminase (AID) is crucial for immunoglobulin gene diversification but also induces chromosomal translocations.
  • Understanding specific miRNA-mRNA interactions in vivo is essential for elucidating physiological roles.

Purpose of the Study:

  • To investigate the physiological impact of the microRNA-155 (miR-155) binding site within the activation-induced cytidine deaminase (AID) mRNA.
  • To determine the role of miR-155 in regulating AID expression and its downstream consequences on chromosomal translocations.

Main Methods:

  • Generation of Aicda(155) mutant mice with a disrupted miR-155 binding site in the AID 3'-untranslated region.
  • Analysis of AID mRNA and protein levels, including mRNA half-life.
  • Assessment of Myc-Igh translocation frequency in Aicda(155) mice and miR-155-deficient mice.

Main Results:

  • The Aicda(155) mutation led to increased steady-state AID mRNA and protein levels due to enhanced mRNA stability.
  • A high frequency of Myc-Igh translocations was observed in Aicda(155) mice.
  • miR-155-deficient mice exhibited a more pronounced translocation phenotype compared to Aicda(155) mice.

Conclusions:

  • miR-155 negatively regulates AID expression by targeting its mRNA, thereby controlling AID-induced translocations.
  • miR-155 functions as a tumor suppressor by mitigating the generation of potentially oncogenic translocations mediated by AID.
  • This study elucidates a critical mechanism by which miR-155 contributes to genomic stability in B lymphocytes.

More Related Videos

Genome-wide Analysis of HDAC Inhibitor-mediated Modulation of microRNAs and mRNAs in B Cells Induced to Undergo Class-switch DNA Recombination and Plasma Cell Differentiation11:06

Genome-wide Analysis of HDAC Inhibitor-mediated Modulation of microRNAs and mRNAs in B Cells Induced to Undergo Class-switch DNA Recombination and Plasma Cell Differentiation

Published on: September 20, 2017

Identifying Targets of Human microRNAs with the LightSwitch Luciferase Assay System using 3'UTR-reporter Constructs and a microRNA Mimic in Adherent Cells07:19

Identifying Targets of Human microRNAs with the LightSwitch Luciferase Assay System using 3'UTR-reporter Constructs and a microRNA Mimic in Adherent Cells

Published on: September 28, 2011

Related Concept Videos

MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns (non-coding regions of a gene) or intergenic regions (stretches of DNA present between genes). Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself, forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA...
MicroRNAs01:22

MicroRNAs

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After the pre-miRNA ends...
Experimental RNAi02:15

Experimental RNAi

RNA interference (RNAi) is a cellular mechanism that inhibits gene expression by suppressing its transcription or activating the RNA degradation process. The mechanism was discovered by Andrew Fire and Craig Mello in 1998 in plants. Today, it is observed in almost all eukaryotes, including protozoa, flies, nematodes, insects, parasites, and mammals. This precise cellular mechanism of gene silencing has been developed into a technique that provides an efficient way to identify and determine the...
Induced Pluripotent Stem Cells01:06

Induced Pluripotent Stem Cells

Stem cells are undifferentiated cells that divide and produce different cell types. Ordinarily, cells that have differentiated into a specific cell type are terminally differentiated; however, scientists have found a way to reprogram these mature cells so that they dedifferentiate and return to an unspecialized, proliferative state. These cells are pluripotent like embryonic stem cells—able to produce all cell types—and are called induced pluripotent stem cells (iPSCs).
Somatic cells are...
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the daughter...