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Modifiers of the jumonji mutation downregulate cyclin D1 expression and cardiac cell proliferation

Tadayuki Ohno1, Kuniko Nakajima, Mizuyo Kojima

  • 1Mitsubishi Kagaku Institute of Life Sciences (MITILS), 11 Minamiooya, Machida, Tokyo 194-8511, Japan.

Biochemical and Biophysical Research Communications
|April 15, 2004
PubMed

Insights

Genetic background significantly impacts jumonji (jmj) mutations in mice. In BALB/c mice, jmj mutation modifiers properly downregulate cardiac cell proliferation by repressing cyclin D1 expression, preventing hyperproliferation.

Area of Science:

  • Developmental biology
  • Cardiovascular research
  • Genetics

Background:

  • Cell proliferation is crucial for tissue morphogenesis and tightly regulated.
  • Jumonji (jmj) deficient mice on a C3H/He background exhibit cardiac myocyte hyperproliferation, leading to embryonic lethality around day 11.5.
  • Jumonji (jmj) is implicated in repressing cyclin D1 expression, a key factor in downregulating cardiac myocyte proliferation.

Purpose of the Study:

  • To investigate the role of genetic background in modifying the effects of jumonji (jmj) mutations on cardiac cell proliferation.
  • To determine if the BALB/c genetic background can suppress the cardiac hyperproliferation phenotype observed in jmj deficient mice.

Main Methods:

  • Comparative analysis of jmj mutant mice on different genetic backgrounds (C3H/He vs. BALB/c).
  • Assessment of cardiac myocyte proliferation rates in jmj mutant embryos.
  • Evaluation of cyclin D1 gene expression levels in cardiac tissues.

Main Results:

  • Jmj mutant mice on a BALB/c background did not display cardiac hyperproliferation.
  • Cell proliferation and cyclin D1 expression were properly downregulated in the cardiac ventricles of jmj mutant mice with a BALB/c background.
  • The BALB/c genetic background appears to possess modifier(s) that can downregulate cardiac cell proliferation.

Conclusions:

  • Genetic background plays a critical role in modulating the cardiac phenotype associated with jumonji (jmj) mutations.
  • Modifier genes present in the BALB/c background can effectively repress cyclin D1 expression, thereby controlling cardiac cell proliferation.
  • These findings highlight the complex interplay between genetic background and gene function in developmental processes.

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