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Updated: Aug 12, 2026
In ovo Expression of MicroRNA in Ventral Chick Midbrain
Published on: September 16, 2013
Expression of the microphthalmia-associated basic helix-loop-helix leucine zipper transcription factor Mi in avian
N Planque1, N Turque, K Opdecamp
1Centre National de la Recherche Scientifique EP 560, Institut Pasteur de Lille, France.
Abstract:
The microphthalmia gene (mi) appears to be required for pigment cell development, based on its mutation in mi mice. The mi gene encodes a basic helix-loop-helix leucine zipper transcription factor (Mi) with tissue-restricted expression. To investigate the role of mi in cell proliferation and pigmentation, we transfected neuroretina (NR) cells with a recombinant virus expressing the murine mi cDNA. The virus induced the proliferation of chicken NR cells in response to fibroblast growth factor 2, which enabled them to form colonies in soft agar. In contrast to control cultures, transfected chicken NR cells or quail NR cells became rapidly pigmented and strongly expressed the QNR-71 mRNA encoding a melanosomal protein. These results demonstrate that Mi not only acts as pigmentation inducer but is also able to modulate the response of cells to growth factors.
Insights
The microphthalmia (mi) gene product, Mi, induces pigmentation and modulates cell proliferation in response to growth factors. This study shows Mi
Area of Science:
- Developmental biology
- Genetics
- Cell biology
Background:
- The microphthalmia (mi) gene is crucial for pigment cell development.
- The mi gene encodes a basic helix-loop-helix leucine zipper transcription factor (Mi).
- Mi exhibits tissue-restricted expression patterns.
Purpose of the Study:
- To investigate the role of the mi gene in cell proliferation.
- To determine the function of Mi in cellular pigmentation.
- To explore Mi's interaction with growth factors.
Main Methods:
- Transfection of neuroretina (NR) cells with a recombinant virus encoding murine mi cDNA.
- Stimulation of NR cells with fibroblast growth factor 2.
- Assessment of cell proliferation, colony formation in soft agar, and pigmentation.
- Analysis of QNR-71 mRNA expression, a marker for melanosomal proteins.
Main Results:
- Mi transfection induced proliferation of chicken NR cells in response to fibroblast growth factor 2.
- Transfected NR cells formed colonies in soft agar, indicating enhanced proliferation.
- Chicken and quail NR cells transfected with Mi exhibited rapid pigmentation.
- QNR-71 mRNA expression was significantly upregulated in Mi-transfected cells.
Conclusions:
- Mi acts as a potent inducer of cellular pigmentation.
- Mi modulates cellular responses to growth factors, influencing proliferation.
- The mi gene plays a dual role in both pigment cell development and growth factor signaling.
