Related Experiment Video

Updated: Apr 21, 2026

In Vivo Proximity Biotinylation for Protein Interaction Studies in Paramecium tetraurelia
06:43

In Vivo Proximity Biotinylation for Protein Interaction Studies in Paramecium tetraurelia

Published on: September 12, 2025

1.5K

A developmental condensin I complex assists the Paramecium PiggyMac domesticated transposase during programmed DNA

Thomas Balan1, Mélanie Bazin-Gélis2, Marc Guérineau2

  • 1Université Paris Cité, CNRS, Institut Jacques Monod, Paris 75013, France.

Nucleic Acids Research
|April 20, 2026
PubMed

Insights

A specialized condensin complex is essential for programmed DNA elimination (PDE) in Paramecium. This developmental condensin targets the PiggyMac (Pgm) endonuclease machinery to DNA cleavage sites for removing mobile genetic elements.

Area of Science:

  • Molecular Biology
  • Genetics
  • Cell Biology

Background:

  • Eukaryotes employ programmed DNA elimination (PDE) to manage mobile genetic elements.
  • The PiggyMac (Pgm) endonuclease and its PgmL partners are crucial for PDE in Paramecium, but their targeting mechanism is unknown.

Purpose of the Study:

  • To elucidate the targeting mechanism of the Pgm endonuclease machinery during programmed DNA elimination (PDE).
  • To investigate the role of condensin I in the DNA elimination process.

Main Methods:

  • Proximity proteome analysis of Pgm and PgmL4.
  • Depletion of specific condensin I subunits.
  • Immunoprecipitation assays.
  • Subnuclear localization studies.

Main Results:

  • Condensin I subunits were identified in proximity to Pgm and PgmL4, forming a complex essential for PDE.
  • This developmental condensin localizes to developing somatic nuclei and is required for Pgm and PgmL localization.
  • Depletion of developmental condensin subunits phenocopies Pgm depletion, blocking DNA elimination.
  • Functional and physical interactions between condensin I and the Pgm/PgmL DNA cleavage machinery were demonstrated.

Conclusions:

  • A specialized condensin I complex plays a critical role in targeting the Pgm endonuclease machinery for programmed DNA elimination (PDE).
  • This interaction is vital for managing transposable elements in the somatic nucleus of Paramecium.
  • Findings reveal a novel link between nuclear architecture and DNA cleavage machinery in genome defense.

More Related Videos

Author Spotlight: Establishing CENP-E Knockout HeLa Cells – A Novel Approach to Study Kinesin-7 CENP-E Biology and its Inhibitors11:49

Author Spotlight: Establishing CENP-E Knockout HeLa Cells – A Novel Approach to Study Kinesin-7 CENP-E Biology and its Inhibitors

Published on: June 23, 2023

1.4K
Generation of Genomic Deletions in Mammalian Cell Lines via CRISPR/Cas909:40

Generation of Genomic Deletions in Mammalian Cell Lines via CRISPR/Cas9

Published on: January 3, 2015

97.0K

Related Concept Videos

Condensins02:15

Condensins

Condensins are large protein complexes that use ATP to fuel the assembly of chromosomes during mitosis. They transform the tangled, shapeless mass of post-interphase DNA into individualized chromosomes by compacting, organizing, and segregating chromosomal DNA.
The plant and animal cells contain two types of condensin complexes—condensin I and condensin II. Both complexes have five subunits: two SMC (Structural Maintenance of Chromosomes) subunits, a kleisin subunit, and two HEAT-repeat...
5.0K
Condensins02:15

Condensins

2.3K
piRNA - Piwi-interacting RNAs02:57

piRNA - Piwi-interacting RNAs

PIWI-interacting RNAs, or piRNAs, are the most abundant short non-coding RNAs. More than 20,000 genes have been found in humans that code for piRNAs while only 2000 genes have been found for miRNAs. piRNAs can act at the transcriptional and post-transcriptional levels and have a vital role in silencing transposable elements present in germ cells. They are also involved in epigenetic silencing and activation. Previously, they were thought to function only in germ cells but new evidence suggests...
7.9K
DNA-only Transposons02:57

DNA-only Transposons

DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
19.1K
Overview of Transposition and Recombination02:13

Overview of Transposition and Recombination

Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
21.3K
Translesion DNA Polymerases02:10

Translesion DNA Polymerases

Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
12.0K