Imprinted X chromosome inactivation in marsupials: The paternal X arrives at the egg with a silent DNA methylation profile.
Proc Natl Acad Sci U S A
; 121(36): e2412185121, 2024 Sep 03.
Article
in En
| MEDLINE
| ID: mdl-39190362
ABSTRACT
X chromosome inactivation (XCI) is an epigenetic process that results in the transcriptional silencing of one X chromosome in the somatic cells of females. This phenomenon is common to both eutherian and marsupial mammals, but there are fundamental differences. In eutherians, the X chosen for silencing is random. DNA methylation on the eutherian inactive X is high at transcription start sites (TSSs) and their flanking regions, resulting in universally high DNA methylation. This contrasts XCI in marsupials where the paternally derived X is always silenced, and in which DNA methylation is low at TSSs and flanking regions. Here, we examined the DNA methylation status of the tammar wallaby X chromosome during spermatogenesis to determine the DNA methylation profile of the paternal X prior to and at fertilization. Whole genome enzymatic methylation sequencing was carried out on enriched flow-sorted populations of premeiotic, meiotic, and postmeiotic cells. We observed that the X displayed a pattern of DNA methylation from spermatogonia to mature sperm that reflected the inactive X in female somatic tissue. Therefore, the paternal X chromosome arrives at the egg with a DNA methylation profile that reflects the transcriptionally silent X in adult female somatic tissue. We present this epigenetic signature as a candidate for the long sought-after imprint for paternal XCI in marsupials.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
X Chromosome
/
DNA Methylation
/
X Chromosome Inactivation
Limits:
Animals
Language:
En
Journal:
Proc Natl Acad Sci U S A
/
Proc. Natl. Acad. Sci. U. S. A
/
Proceedings of the national academy of sciences of the United States of America
Year:
2024
Document type:
Article
Affiliation country:
Australia
Country of publication:
United States