Related Experiment Videos
Gene structure of the P100 serine-protease component of the human Ra-reactive factor
Y Takayama1, F Takada, M Nowatari
1Department of Molecular Biology, Kitasato University School of Medicine, Kanagawa, Japan. ytakayam@kitasato-u.ac.jp
Abstract:
The Ra-reactive factor (RaRF) is a complement dependent anti-microbial factor that reacts with numerous microorganisms such as viruses, bacteria, fungi and protozoa. It is a complex of a mannan-binding lectin (MBL) and the serine protease, P100 (MASPI). P100 activates the C4 component of the complement system and its domain organization is similar to C1r and C1s. In this study, determination was made of the structure of the human P100 gene which was found longer than 67 kbp and to be comprised of 16 exons. Its non-protease region consisted of 10 exons, as in the case of C1r and C1s, and the introns were found present in the boundary separating two CUB domains, an EGF-like domain and two CCP domains and each CUB and CCP domain contained extra internal introns. The serine protease region was comprised of 6 exons in contrast to C1r and C1s, either of which consists of a single exon. The exon-intron structure was found to reflect the evolution of these molecules and P100 to have derived earlier in the stage of evolution than C1r or C1s.
Insights
The Ra-reactive factor (RaRF) P100 gene has a unique exon-intron structure, differing from related complement proteins. This structure suggests P100 evolved earlier than C1r or C1s.
Area of Science:
- Immunology
- Molecular Biology
- Evolutionary Biology
Background:
- The Ra-reactive factor (RaRF) is a complement-dependent antimicrobial factor.
- RaRF comprises mannan-binding lectin (MBL) and the serine protease P100 (MASPI).
- P100 activates the C4 complement component and shares domain similarity with C1r and C1s.
Purpose of the Study:
- To determine the exon-intron structure of the human P100 gene.
- To compare the P100 gene structure with those of C1r and C1s.
- To infer evolutionary relationships based on gene structure.
Main Methods:
- Human P100 gene structure determination.
- Exon and intron analysis.
- Comparative gene structure analysis with C1r and C1s.
Main Results:
- The human P100 gene is over 67 kbp and consists of 16 exons.
- The non-protease region has 10 exons, similar to C1r and C1s, with introns at domain boundaries.
- The serine protease region has 6 exons, unlike the single exon in C1r and C1s.
Conclusions:
- The exon-intron structure of P100 reflects its evolutionary history.
- P100 likely represents an earlier evolutionary stage compared to C1r and C1s.
- Gene structure provides insights into the evolution of complement system proteases.