Knocking down caspase-3 by RNAi reduces mortality in Pacific white shrimp Penaeus (Litopenaeus) vannamei challenged with a low dose of white-spot syndrome virus.
Apoptosis has long been observed in viral target organs of white-spot syndrome virus (WSSV)-infected shrimp and whether the phenomenon helps the shrimp to survive the infection or is a factor leading to mortality is still controversial. If the shrimp mortality is a result of triggered apoptosis, then inactivation of caspase-3, a key protein in the induction of apoptosis, should improve shrimp survival upon challenge with WSSV. To test this prediction, we identified and characterized a caspase-3 homologue (cap-3) from the Pacific white shrimp Penaeus (Litopenaeus) vannamei and used this information to silence cap-3 expression by RNA interference prior to WSSV challenge. After confirming the efficacy of cap-3 silencing, its effects on mortality at high and low doses of WSSV were evaluated. In a high-dose WSSV challenge, cap-3 silencing had no significant effect on WSSV-induced mortality, except for a delay in mean time to death. However, at a low-dose WSSV challenge, cap-3 silencing correlated with a lower level of cumulative mortality, relative to silencing of a control gene, suggesting that apoptosis may exacerbate rather than decrease mortality in WSSV-challenged shrimp.
Rijiravanich
Anchukorn
A
Department of Anatomy, Faculty of Science, Mahidol University, 272 Rama 6 Road, Phayathai, Rajdhevee, Bangkok 10400, Thailand.
Browdy
Craig L
CL
Withyachumnarnkul
Boonsirm
B
D000818:Animals; D053148:Caspase 3 / Q000235:genetics* / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000201:enzymology / Q000235:genetics* / Q000821:virology*; D034622:RNA Interference; D016019:Survival Analysis; D013997:Time Factors; D046848:White spot syndrome virus 1
D053148:Caspase 3