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Published on: December 1, 2011
Genetic characterization of Indian type O FMD virus 3A region in context with host cell preference
V Maroudam1, S B Nagendrakumar, P N Rangarajan
1Research and Development Centre, Indian Immunologicals Limited, Rakshapuram, Gachibowli Post, Hyderabad 500 032, Andhra Pradesh, India.
Abstract:
The 3A region of foot-and-mouth disease virus has been implicated in host range and virulence. For example, amino acid deletions in the porcinophilic strain (O/TAW/97) at 93-102aa of the 153 codons long 3A protein have been recognized as the determinant of species specificity. In the present study, 18 type O FMDV isolates from India were adapted in different cell culture systems and the 3A sequence was analyzed. These isolates had complete 3A coding sequence (153aa) and did not exhibit growth restriction in cells based on species of origin. The 3A region was found to be highly conserved at N-terminal half (1-75aa) but exhibited variability or substitutions towards C-terminal region (80-153). Moreover the amino acid substitutions were more frequent in recent Indian buffalo isolates but none of the Indian isolates showed deletion in 3A protein, which may be the reason for the absence of host specificity in vitro. Further inclusive analysis of 3A region will reveal interesting facts about the variability of FMD virus 3A region in an endemic environment.
Insights
Foot-and-mouth disease virus (FMDV) 3A protein deletions determine host specificity. Indian FMDV isolates lack these deletions, showing no in vitro host restriction, suggesting conserved 3A sequences contribute to broad host range.
Area of Science:
- Virology
- Molecular Biology
- Animal Health
Background:
- The 3A region of foot-and-mouth disease virus (FMDV) is crucial for host range and virulence.
- Amino acid deletions in the 3A protein (e.g., 93-102aa in O/TAW/97) are linked to FMDV's porcinophilic specificity.
Purpose of the Study:
- To analyze the 3A coding sequence of 18 type O FMDV isolates from India.
- To investigate the correlation between 3A sequence variations and host specificity in FMDV.
Main Methods:
- Adaptation of 18 Indian type O FMDV isolates in various cell culture systems.
- Sequencing and comparative analysis of the FMDV 3A protein coding region (153 amino acids).
Main Results:
- All Indian FMDV isolates possessed a complete 3A coding sequence (153aa) without deletions.
- The N-terminal half (1-75aa) of the 3A region was highly conserved, while the C-terminal region (80-153aa) showed variability and substitutions.
- Amino acid substitutions were more prevalent in recent Indian buffalo isolates; no isolates exhibited deletions associated with host specificity.
Conclusions:
- The absence of 3A protein deletions in Indian FMDV isolates correlates with their lack of in vitro host specificity.
- Variability in the C-terminal region of the 3A protein may influence FMDV adaptation in endemic environments.
- Further research on the FMDV 3A region is needed to understand its variability in endemic settings.
