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Characterization of R-ras3/m-ras null mice reveals a potential role in trophic factor signaling

Nelson Nuñez Rodriguez1, Ivy N L Lee, Asoka Banno

  • 1Department of Oncological Sciences, The Mount Sinai School of Medicine, New York, New York 10029, USA.

Molecular and Cellular Biology
|September 19, 2006
PubMed

Insights

M-Ras, a RAS-superfamily protein, is highly expressed in the central nervous system. M-Ras null mice show no developmental defects, suggesting it may not be essential for embryogenesis or postnatal development.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Cell Biology

Background:

  • R-Ras3/M-Ras is a GTP-binding protein within the RAS superfamily.
  • High M-Ras expression is noted in the central nervous system, influencing cytoskeletal organization, cell transformation, survival, and differentiation.
  • The precise physiological roles of M-Ras in embryogenesis and postnatal development remain unclear.

Purpose of the Study:

  • To investigate the role of M-Ras in embryonic and postnatal development.
  • To determine the expression and activation patterns of M-Ras in astrocytes.
  • To assess the impact of M-Ras deficiency on neurological development and cellular signaling pathways.

Main Methods:

  • Utilized a specific M-Ras antibody to detect M-Ras expression in neural cells.
  • Investigated M-Ras activation by trophic factors (EGF, bFGF, HGF) in primary astrocytes.
  • Generated and analyzed M-Ras null mice for phenotypic and neurological abnormalities.
  • Assessed mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathway activation in M-Ras deficient astrocytes.

Main Results:

  • M-Ras is highly expressed in both neurons and astrocytes.
  • Epidermal growth factor (EGF) induced a more sustained activation of M-Ras in astrocytes compared to prototypic Ras.
  • M-Ras null mice exhibited normal phenotypes without detectable morphological or neurological defects.
  • Primary astrocytes from M-Ras null mice showed no significant alterations in MAPK and PI3K pathway activation in response to trophic factors.

Conclusions:

  • M-Ras is expressed in astrocytes and activated by trophic factors, with sustained activation by EGF.
  • Despite its expression and activation, M-Ras appears dispensable for normal embryogenesis and postnatal development in mice.
  • The absence of M-Ras does not substantially impair key signaling pathways like MAPK and PI3K in astrocytes during development.

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