Related Experiment Videos
Developmental changes of DNA methylation pattern of embryonic chick pepsinogen gene
K Fukuda1, M Ichinose, H Saiga
1Zoological Institute, Faculty of Science, University of Tokyo.
Insights
DNA methylation regulates organ-specific expression of embryonic chick pepsinogen (ECPg) by altering methylation patterns in the ECPg gene. However, stage-specific expression appears to be controlled by different mechanisms.
Area of Science:
- Developmental Biology
- Epigenetics
- Molecular Biology
Background:
- Embryonic chick pepsinogen (ECPg) expression is specific to the proventriculus (glandular stomach) in embryonic chicks.
- Understanding the regulatory mechanisms controlling tissue-specific and developmental gene expression is crucial.
Purpose of the Study:
- To investigate the role of DNA methylation in the organ-specific and developmental stage-specific expression of the ECPg gene.
- To analyze methylation patterns of the ECPg gene in different chick organs during development.
Main Methods:
- Analysis of ECPg gene methylation status using methylation-sensitive restriction enzymes in various embryonic and hatched chick organs.
- Correlation of methylation patterns with the onset and cessation of ECPg gene transcription.
Main Results:
- Demethylation at CCGG sites in the ECPg gene region occurred in the proventriculus post-transcription onset, while these sites remained methylated in non-expressing organs.
- GCGC sites became methylated in non-expressing organs but remained unmethylated in the proventriculus.
- CpG sites showed no methylation changes in the proventriculus after ECPg expression ceased.
Conclusions:
- DNA methylation plays a significant role in regulating the organ-specific expression of the ECPg gene.
- Mechanisms other than DNA methylation likely control the developmental stage-specific expression of ECPg.
Abstract:
Embryonic chick pepsinogen (ECPg) is one of the pepsinogen isozymogens and its expression is restricted to epithelial cells of the embryonic chick proventriculus (glandular stomach). To examine whether DNA methylation is involved in the regulation of organ-specific and developmental stage-specific expression of ECPg gene, we analyzed the extent of methylation of ECPg gene in normal embryonic and hatched chick organs using methylation-sensitive restriction enzymes. In the proventriculus some CCGG sites underwent demethylation in the gene region after the onset of transcription of the ECPg gene. By contrast, these sites were kept methylated throughout the development in the other organs which do not express ECPg gene. GCGC sites in the gene region became methylated in organs which do not express the ECPg gene, after the initiation of transcription of the ECPg gene in the proventriculus. In the proventriculus, GCGC sites, which were methylated in other organs, were kept unmethylated throughout the development. The methylation state of CpG sites showed no change in the proventriculus of a chick 2 weeks after hatching when the expression of the ECPg gene had completely ceased. The data presented here demonstrate that the DNA methylation is involved in the regulation of organ-specific expression, but stage-specific expression might be brought about by some other mechanisms.