Abstract
Purpose: :
Epidemic keratoconjunctivitis (EKC) is a highly contagious adenovirus ocular infection caused by human adenovirus (HAdV) serotypes 8, 19, and 37. Long-term visual morbidity in EKC can occur due to persistent corneal inflammation. The complete genomic sequences of the EKC HAdV serotypes have yet to be identified. We sequenced the complete genome of HAdV-19 and compared this serotype to other subgroup D adenoviruses not commonly associated with EKC.
Methods: :
HAdV-19 was isolated directly from a patient with EKC, and the viral serotype confirmed by the State of Oklahoma Department of Health. Standard PCR methodology was used to amplify regions of the genome to be sequenced. Annotation was performed with TIGR’s Annotation Engine, NCBI’s open reading frame finder, and GeneMark software. Global pairwise sequence comparison of subgroup D adenoviruses was performed with mVISTA LAGAN software. Amino acid sequences were compared using MEGA 3.1 and JVirGel software.
Results: :
A 35,231 base pair genome sequence was determined and analyzed. The GC content was 56.5%. We annotated 35 classical protein coding sequences along with 8 hypothetical genes. Genome-wide comparison between HAdV-19 and HAdV-37 revealed a 98.6% sequence similarity. Whole genome comparisons with mVISTA LAGAN software of HAdV-19 with subgroup D adenoviruses not associated with EKC demonstrated differences in the penton, hexon, E3, and fiber protein coding regions. Virtual 2D gel analysis identified differences in the molecular weight and pI of specific HAdV proteins otherwise shown to be similar.
Conclusions: :
Differences in the penton, hexon, E3, and fiber protein coding regions suggest potential mechanisms for the unique ocular tropism of HAdV-19. Differences in the 2D gel migration of otherwise similar proteins emphasizes the potential diversity in proteins thought to have equivalent functions. Future experiments will be necessary to determine if unique regions within the HAdV-19 genome contribute to ocular pathogenesis in EKC.
Keywords: adenovirus • genetics • keratitis