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Identification and expression analysis of minichromosome maintenance proteins in the silkworm, Bombyx mori
Kohji Yamamoto1, Yoichi Aso, Hiroshi Fujii
1Laboratories of Insect Genetic Resources, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. yamamok@agr.kyushu-u.ac.jp
Abstract:
The minichromosome maintenance protein (MCM) family is involved in the regulatory role of DNA replication in eukaryotic organisms. A cDNA encoding of an MCM of the silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), was cloned by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequenced. The resultant amino acid sequence and phylogenetic analysis revealed high identity to MCM, and specifically to MCM7, of vertebrates and invertebrates. An RT-PCR showed that the bmMCM7 transcript was present in the ovaries, testes, silk glands, and fat bodies of larval silkworms. Expression plasmids were transformed into competent Escherichia coli and overexpressed. This is the first report on the identification of MCM helicase of the silkworm, B. mori.
Insights
Researchers identified the minichromosome maintenance protein 7 (MCM7) in the silkworm, Bombyx mori. This MCM helicase is crucial for DNA replication and found in various silkworm tissues.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The minichromosome maintenance (MCM) protein family plays a vital role in regulating DNA replication in eukaryotic cells.
- Understanding MCM proteins across different species is essential for comprehending DNA replication mechanisms.
Purpose of the Study:
- To clone and characterize the minichromosome maintenance protein 7 (MCM7) from the silkworm, Bombyx mori.
- To investigate the tissue-specific expression of the silkworm MCM7 (bmMCM7) transcript.
Main Methods:
- Cloning of Bombyx mori MCM7 (bmMCM7) cDNA using reverse transcriptase-polymerase chain reaction (RT-PCR).
- Sequencing of the cDNA and analysis of the resultant amino acid sequence.
- Phylogenetic analysis to determine evolutionary relationships.
- RT-PCR to analyze bmMCM7 transcript distribution in larval tissues.
- Overexpression of bmMCM7 in Escherichia coli.
Main Results:
- The cloned cDNA encoded a protein with high sequence identity to MCM7 from other vertebrates and invertebrates.
- Phylogenetic analysis confirmed its classification as an MCM7 homolog.
- The bmMCM7 transcript was detected in ovaries, testes, silk glands, and fat bodies of larval silkworms.
- The protein was successfully overexpressed in E. coli.
Conclusions:
- This study reports the first identification and characterization of an MCM helicase, specifically MCM7, in the silkworm, Bombyx mori.
- The findings provide insights into the molecular basis of DNA replication in silkworms and highlight the conserved nature of MCM7 across diverse species.
