Related Experiment Videos
Characterization of adenovirus subgenus D fiber genes
1Nationales Referenzzentrum für Adenoviren, Medizinische Hochschule Hannover, Federal Republic of Germany.
Abstract:
The fiber genes of human adenovirus types 8, 9, 15, and two genome types of intermediate adenovirus 15/H9, all belonging to subgenus D, were sequenced and the nucleotide and predicted amino acid sequences compared. The analyzed peptide sequences were consistent with the structural domains described for other adenoviruses: an amino-terminal tail region, an intervening shaft region composed of eight repeating 15-amino-acid segments, and a carboxy-terminal knob. Furthermore, several highly conserved sequences could be confirmed. The fiber genes of AV9 and the AV15/H9 intermediate strains were 100% identical, not only in the coding region, but also in the presented 5'- and 3'-flanking regions. These findings support the hypothesis that intermediate strains arise by recombination of two serologically different parent viruses. The predicted AV8, AV9, and AV15/H9 polypeptides showed an overall homology of 92%. In the knob regions, AV8 and AV9; AV15/H9 intermediate strains revealed nine mismatches. AV8 is the main causative agent of epidemic keratoconjunctivitis in man, whereas AV9 and the AV15/H9 intermediate strains only infrequently cause acute follicular conjunctivitis. Since the knob is the component responsible for interaction with the cell receptor, these differences in the receptor binding sites should be expected to play an important role in the differences in pathogenicity.
Insights
Sequencing human adenovirus fiber genes revealed high similarity, supporting recombination as a cause of intermediate strains. Differences in the knob region may explain varying disease severity.
Area of Science:
- Virology
- Molecular Biology
Background:
- Human adenoviruses (HAdVs) are significant pathogens.
- Subgenus D adenoviruses, including types 8 and 9, cause various conjunctivitis forms.
- Intermediate strains suggest genetic exchange between adenovirus types.
Purpose of the Study:
- To sequence and compare the fiber genes of human adenovirus types 8, 9, and intermediate 15/H9 strains.
- To investigate the genetic basis of adenovirus pathogenicity and strain variation.
Main Methods:
- DNA sequencing of fiber genes from HAdV-8, HAdV-9, and HAdV-15/H9 intermediate strains.
- Bioinformatic analysis of nucleotide and predicted amino acid sequences.
- Comparison of conserved sequences and structural domains (tail, shaft, knob).
Main Results:
- Fiber genes of HAdV-9 and HAdV-15/H9 intermediate strains were 100% identical, including flanking regions.
- Overall homology among predicted polypeptides of HAdV-8, HAdV-9, and HAdV-15/H9 was 92%.
- Nine mismatches were identified in the knob regions between HAdV-8, HAdV-9, and HAdV-15/H9.
Conclusions:
- Findings support the hypothesis that intermediate adenovirus strains result from recombination.
- Differences in the fiber knob region, crucial for cell receptor interaction, likely contribute to the distinct pathogenicity of HAdV-8 versus HAdV-9 and intermediate strains.