Related Experiment Video

Updated: Aug 8, 2026

Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling
06:55

Polarized Translocation of Fluorescent Proteins in Xenopus Ectoderm in Response to Wnt Signaling

Published on: May 26, 2011

Regulation of Raf-1-dependent signaling during early Xenopus development

A M MacNicol1, A J Muslin, E L Howard

  • 1Daiichi Research Center, Cardiovascular Research Institute, University of California at San Francisco 94143, USA.

Molecular and Cellular Biology
|December 1, 1995
PubMed

Insights

Following fertilization, the Raf-1/MEK/MAP kinase (MAPK) pathway is turned off to allow normal embryonic cell cycle progression. Reactivation of MAPK signaling causes cell cycle arrest and embryonic lethality.

Area of Science:

  • Developmental biology
  • Cell signaling
  • Molecular biology

Background:

  • The Raf-1/MEK/MAP kinase (MAPK) pathway regulates cellular differentiation and proliferation.
  • Understanding the precise regulation of this pathway is crucial during early embryonic development.

Purpose of the Study:

  • To investigate the regulation of the Raf-1/MEK/MAPK pathway during Xenopus laevis embryonic development.
  • To determine the role of this pathway in cell cycle progression following fertilization.

Main Methods:

  • Assessed Raf-1, MEK, and MAPK activities in Xenopus embryos at different developmental stages.
  • Microinjected oncogenic Raf-1 RNA to observe effects on MAPK activity and cell cycle progression.

Main Results:

  • Raf-1, MEK, and MAPK activities were undetectable from fertilization until blastula stages (stage 8).
  • Inappropriate MAPK reactivation via oncogenic Raf-1 RNA led to metaphase cell cycle arrest and embryonic lethality.
  • Demonstrated an essential requirement for MAPK pathway inactivation for normal cell cycle progression post-fertilization.

Conclusions:

  • The inactivation of the Raf-1/MEK/MAPK pathway is critical for synchronous cell divisions in early Xenopus embryos.
  • Cytostatic factor effects during early development are mediated through MEK and MAPK signaling.

More Related Videos

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients08:10

Using Confocal Analysis of Xenopus laevis to Investigate Modulators of Wnt and Shh Morphogen Gradients

Published on: December 14, 2015

Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development09:32

Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development

Published on: June 15, 2017

Related Concept Videos

Determination01:51

Determination

During embryogenesis, cells become progressively committed to different fates through a two-step process: specification followed by determination. Specification is demonstrated by removing a segment of an early embryo, “neutrally” culturing the tissue in vitro—for example, in a petri dish with simple medium—and then observing the derivatives. If the cultured region gives rise to cell types that it would normally generate in the embryo, this means that it is specified. In contrast, determination...
Mechanism of Lamellipodia Formation01:31

Mechanism of Lamellipodia Formation

Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
Regulation of Angiogenesis and Blood Supply01:24

Regulation of Angiogenesis and Blood Supply

Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits.  Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...