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Stimulation of MCM3 gene expression in osteoblast by low level laser irradiation
M Yamamoto1, K Tamura, K Hiratsuka
1Department of Biochemistry, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Abstract:
Biostimulatory effect of cell proliferation and bone formation by laser irradiation has been reported, however, very little is known about the molecular basis of mechanisms. We previously constructed the cDNA library of mouse osteoblastic cells (MC3T3-E1) which enhanced gene expression by laser irradiation using a subtracted gene cloning procedure. In the present study, we focused on a gene clone, designated as MCL-140, which exhibited the high homology of DNA sequence with mouse minichromosome maintenance (MCM) 3 gene. MCM3 is involved in the initiation of DNA replication as licensing factor in eukaryotic cells. Nucleotide sequence of MCL-140 insert was determined and assessed in the nucleic acid databases. The transcription level of MCL-140 was examined by Northern blot analysis. The DNA sequences of clone MCL-140 insert exhibited 96.2% homology with MCM 3 gene coding P1 protein. Higher MCM3 mRNA levels were observed in laser-irradiated cells compared to the levels in non-irradiated cells: furthermore, radiolabelled thymidine incorporation was increased by laser irradiation. These findings suggest that low-level laser irradiation may enhance DNA replication and play a role in stimulating proliferation of osteoblast through the enhancement of the MCM3 gene expression.
Insights
Low-level laser irradiation stimulates osteoblast proliferation by enhancing minichromosome maintenance 3 (MCM3) gene expression, promoting DNA replication and bone formation.
Area of Science:
- Biomedical Engineering
- Molecular Biology
- Cell Biology
Background:
- Laser irradiation shows biostimulatory effects on cell proliferation and bone formation.
- The molecular mechanisms underlying laser irradiation's effects on osteoblasts are not well understood.
- Previous work identified osteoblastic genes upregulated by laser irradiation.
Purpose of the Study:
- To investigate the molecular basis of laser irradiation's effect on osteoblast proliferation.
- To identify specific genes involved in laser-induced osteoblast responses.
- To elucidate the role of minichromosome maintenance 3 (MCM3) in laser-stimulated osteogenesis.
Main Methods:
- Construction of a cDNA library from laser-irradiated mouse osteoblastic cells (MC3T3-E1).
- Gene cloning and sequencing of differentially expressed genes, focusing on clone MCL-140.
- Northern blot analysis to assess MCM3 mRNA levels.
- Measurement of radiolabeled thymidine incorporation to evaluate DNA replication.
Main Results:
- Clone MCL-140 showed 96.2% DNA sequence homology with mouse MCM3 gene.
- Laser irradiation significantly increased MCM3 mRNA levels in osteoblasts.
- Laser irradiation enhanced radiolabeled thymidine incorporation, indicating increased DNA replication.
Conclusions:
- Laser irradiation upregulates the expression of the MCM3 gene in osteoblasts.
- Enhanced MCM3 expression likely stimulates DNA replication and osteoblast proliferation.
- Low-level laser irradiation may promote bone formation through MCM3-mediated mechanisms.