Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Restarting Stalled Replication Forks

Restarting Stalled Replication Forks

DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...

Gene Conversion

Gene Conversion

Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...

Homologous Recombination

Homologous Recombination

The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...

Fixing Double-strand Breaks

Fixing Double-strand Breaks

The double-stranded structure of DNA has two major advantages. First, it serves as a safe repository of genetic information where one strand serves as the back-up in case the other strand is damaged. Second, the double-helical structure can be wrapped around proteins called histones to form nucleosomes, which can then be tightly wound to form chromosomes. This way, DNA chains up to 2 inches long can be contained within microscopic structures in a cell. A double-stranded break not only damages...

Fertilization

Fertilization

During fertilization, an egg and sperm cell fuse to create a new diploid structure. In humans, the process occurs once the egg has been released from the ovary, and travels into the fallopian tubes. The process requires several key steps: 1) sperm present in the genital tract must locate the egg; 2) once there, sperm need to release enzymes to help them burrow through the protective zona pellucida of the egg; and 3) the membranes of a single sperm cell and egg must fuse, with the sperm...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Follow-up to 'Glycaemic management in a child with ornithine transcarbamylase deficiency undergoing cardiac surgery with hypothermic cardiopulmonary bypass'.

Anaesthesia reports·2024

Same author

Glycaemic management in a child with ornithine transcarbamylase deficiency undergoing cardiac surgery with hypothermic cardiopulmonary bypass.

Anaesthesia reports·2022

Same author

Enhancement of the spin polarization of an Fe<sub>3</sub>O<sub>4</sub>(100) surface by nitric oxide adsorption.

Physical chemistry chemical physics : PCCP·2018

Same author

Reversible switching of the spin state in a manganese phthalocyanine molecule by atomic nitrogen.

Physical chemistry chemical physics : PCCP·2017

Same author

Pheophorbide a Content and Chlorophyllase Activity in Green Tea.

Bioscience, biotechnology, and biochemistry·2016

Same author

Half-metallicity induced by boron adsorption on an Fe3O4(100) surface.

Physical chemistry chemical physics : PCCP·2015

Search research articles

Related Experiment Video

Updated: Jul 14, 2026

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Published on: April 21, 2022

Sperm DNA fragmentation: awakening the sleeping genome.

J A Shaman¹, Y Yamauchi, W S Ward

¹Institute for Biogenesis Research, John A. Burns School of Medicine, University of Hawaii, 1960 East-West Road, Honolulu, HI 96822, USA.

Biochemical Society Transactions

|May 22, 2007

Summary

Mammalian sperm can degrade their own DNA via a process involving topoisomerase IIB (TOP2B), similar to apoptosis. This DNA fragmentation is crucial for paternal DNA elimination after fertilization.

More Related Videos

Zygotic Fluorescence Recovery After Photo-bleaching Analysis for Chromatin Looseness That Allows Full-term Development

Zygotic Fluorescence Recovery After Photo-bleaching Analysis for Chromatin Looseness That Allows Full-term Development

Published on: June 12, 2018

Related Experiment Videos

Last Updated: Jul 14, 2026

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Published on: April 21, 2022

Zygotic Fluorescence Recovery After Photo-bleaching Analysis for Chromatin Looseness That Allows Full-term Development

Zygotic Fluorescence Recovery After Photo-bleaching Analysis for Chromatin Looseness That Allows Full-term Development

Published on: June 12, 2018

Area of Science:

Reproductive Biology
Molecular Biology
Genetics

Background:

Mammalian spermatozoa possess a unique DNA degradation mechanism resembling somatic cell apoptosis.
This process involves topoisomerase IIB (TOP2B) in the initial degradation of sperm DNA into loop-sized fragments.
Sperm chromatin fragmentation can be reversed by EDTA, indicating TOP2B's role in DNA breaks and religation.

Purpose of the Study:

To investigate the functional significance of active topoisomerase IIB (TOP2B) within the nucleus of mouse spermatozoa.
To understand the role of TOP2B-mediated DNA breaks in sperm function and paternal DNA fate post-fertilization.

Main Methods:

Induction of TOP2B-mediated DNA breaks in mouse spermatozoa.
Injection of treated spermatozoa into oocytes.
Observation of paternal DNA fate and degradation timing during early embryonic development.

Main Results:

TOP2B-mediated DNA breaks in spermatozoa lead to specific and complete degradation of paternal DNA upon oocyte injection.
The complete digestion of paternal DNA occurs precisely at the initiation of DNA synthesis.
Further degradation of sperm DNA into the entire genome can be mediated by nucleases under specific conditions.

Conclusions:

Active topoisomerase IIB (TOP2B) plays a critical role in the programmed degradation of paternal DNA in mouse zygotes.
This TOP2B-dependent mechanism ensures the selective elimination of the paternal genome, preventing its contribution to the zygote.
The findings highlight a novel pathway for controlling paternal DNA inheritance essential for successful reproduction.