Genomic imprinting in germ cells: imprints are under control

Area of Science:

• Epigenetics
• Genomics
• Developmental Biology

Background:

• Imprinted gene loci are regulated by cis-acting sequences known as imprinting control regions (ICRs).
• ICRs acquire epigenetic marks, primarily DNA methylation, in germ cells.
• These marks dictate monoallelic expression (either paternal or maternal) of imprinted genes in offspring.

Purpose of the Study:

• To review recent findings on the establishment and maintenance of epigenetic imprints at ICRs.
• To focus on the germline acquisition of DNA methylation imprints.
• To explore the interplay of factors involved in imprinting.

Main Methods:

• Literature review of recent studies on epigenetic imprinting.
• Synthesis of findings related to ICR marking and maintenance.
• Analysis of the roles of sequence, chromatin, proteins, and transcription.

Main Results:

• ICRs are marked with specific epigenetic modifications, including DNA methylation, during germ cell development.
• The process involves a combination of primary sequence specificity, chromatin structure, non-histone proteins, and transcriptional activity.
• These factors collectively ensure the correct establishment and maintenance of imprints.

Conclusions:

• Understanding the germline acquisition of DNA methylation at ICRs is crucial for comprehending imprinted gene expression.
• Recent advances highlight the complex interplay of molecular factors in establishing epigenetic memory.
• This review consolidates current knowledge on the mechanisms governing genomic imprinting.