Related Experiment Video
Updated: Jun 19, 2026
10:36
Chromatin Immunoprecipitation from Human Embryonic Stem Cells
Published on: July 22, 2008
Distinctive chromatin in human sperm packages genes for embryo development
Saher Sue Hammoud1, David A Nix, Haiying Zhang
1Howard Hughes Medical Institute, Department of Oncological Sciences, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA.
Nature
|June 16, 2009
Summary
Sperm retain nucleosomes at key developmental gene locations, challenging previous beliefs about limited epigenetic contribution. These retained nucleosomes carry specific histone modifications crucial for early embryo development regulation.
Area of Science:
- Epigenetics
- Developmental Biology
- Sperm Biology
Background:
- Mature human sperm primarily use protamine instead of nucleosomes, leading to the assumption of minimal sperm chromatin epigenetic influence on embryo development.
- Previous understanding suggested limited epigenetic contributions from sperm chromatin due to protamine replacement of nucleosomes.
Purpose of the Study:
- To investigate the distribution and significance of retained nucleosomes and their associated histone modifications in human sperm.
- To determine if sperm chromatin retains epigenetic information relevant to embryonic development.
Main Methods:
- Analysis of nucleosome occupancy in human sperm.
- Mapping of specific histone modifications (H3K4me2, H3K4me3, H3K27me3) at developmental loci.
- Assessment of DNA methylation patterns in sperm promoters.
Main Results:
- Retained nucleosomes are significantly enriched at important developmental loci, including imprinted gene clusters, microRNA clusters, and HOX gene clusters.
- Specific histone modifications like H3K4me3 and H3K27me3 are localized to developmental promoters and regulatory regions, correlating with gene expression states in early embryos.
- Developmental promoters in sperm are generally hypomethylated but gain methylation during differentiation.
Conclusions:
- Sperm chromatin retains extensive epigenetic marking, contrary to previous assumptions.
- These epigenetic marks are specifically localized to developmental regulators and are correlated with key developmental processes, suggesting a significant role in embryo development.
Related Concept Videos
01:41Spermatogenesis
Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of seminiferous tubules. These spermatogonial stem cells divide asymmetrically to give rise to additional stem cells (meaning that these structures “self-renew”), as well as sperm progenitors, called spermatocytes. Importantly, this method of asymmetric mitotic division maintains a population of spermatogonial stem cells in the male reproductive...
01:38Fertilization
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...
02:21Chromatin Packaging
Each human somatic cell contains 6 billion base-pairs of DNA. Each base-pair is 0.34 nm long, which means that each diploid cell contains a staggering 2 meters of DNA. How is such a long DNA strand packed inside a nucleus measuring only 10 - 20 microns in diameter?
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
03:17Inheritance of Chromatin Structures
Epigenetics is the study of inherited changes in a cell's phenotype without changing the DNA sequences. It provides a form of memory for the differential gene expression pattern to maintain cell lineage, position-effect variegation, dosage compensation, and maintenance of chromatin structures such as telomeres and centromeres. For example, the structure and location of the centromere on chromosomes are epigenetically inherited. Its functionality is not dictated or ensured by the underlying DNA...
02:21Chromatin Packaging
Each human somatic cell contains 6 billion base-pairs of DNA. Each base-pair is 0.34 nm long, which means that each diploid cell contains a staggering 2 meters of DNA. How is such a long DNA strand packed inside a nucleus measuring only 10 - 20 microns in diameter?
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
The chromatin
In combination with specialized DNA binding protein called Histones, the DNA double helix forms a compact DNA: protein complex called chromatin. The chromatin itself is further compacted into higher-order structures.
01:32Chromatin Packaging
Each human somatic cell contains 6 billion base pairs of DNA. Each base pair is 0.34 nm long, meaning each diploid cell contains a staggering 2 meters of DNA. This long DNA strand is packed inside a nucleus measuring only 10-20 microns in diameter with the help of specialized DNA-binding proteins called histones. Together they form a compact DNA-protein complex called chromatin. The chromatin is further compacted into higher-order structures. The highest level of compaction is achieved during...