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Developmental changes in the expression of high mobility group chromosomal proteins
M P Crippa1, J M Nickol, M Bustin
1Laboratory of Molecular Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
The Journal of Biological Chemistry
|February 15, 1991
Summary
High mobility group (HMG) chromosomal proteins and their messenger RNAs (mRNAs) significantly change during chicken erythropoiesis. Gene expression shifts between primitive and definitive erythroid lineages, impacting chromatin structure during development.
Area of Science:
- Molecular Biology
- Developmental Biology
- Chromatin Biology
Background:
- High mobility group (HMG) chromosomal proteins are implicated in modulating chromatin structure, influencing cellular development and differentiation.
- Understanding the dynamic expression of HMG proteins during specific developmental processes like erythropoiesis is crucial.
Purpose of the Study:
- To investigate the changes in HMG chromosomal proteins and their mRNA levels during erythropoiesis in chicken embryos.
- To determine if alterations in HMG protein expression correlate with the switch between primitive and definitive erythroid lineages.
Main Methods:
- Analysis of HMG mRNA and protein levels in erythroid cells from different developmental stages (5-day, 7-day, 14-day embryos, and adult circulation).
- Utilized nuclear run-off experiments and Northern blot analysis to assess gene transcription.
- Employed Percoll fractionation to isolate and analyze specific cell populations.
Main Results:
- HMG mRNAs were significantly higher in 5-day embryonic erythroid cells compared to 14-day embryonic cells; adult cells lacked these mRNAs.
- Gene transcription for HMG proteins was confirmed in early primitive and definitive erythroid cells.
- Differential synthesis rates of HMG-14a, HMG-14b, and HMG-17 were observed, with HMG-14a predominant in primitive cells and HMG-14b in definitive cells.
Conclusions:
- The transition from primitive to definitive erythroid lineages during embryogenesis is marked by distinct changes in HMG chromosomal protein gene expression.
- These expression shifts may influence chromatin structure, potentially playing a role in erythroid differentiation, though the precise causal relationship requires further investigation.