FIG 4.
Disrupting the conserved amphipathic N1 TMD restricts viral replication to 33°C. (A) Graph displaying the conservation of the amphipathic characteristic (adjacent polar a and e faces with positive ΔGapp-face values) in 100% of the N1 TMDs from human, avian, and swine IAVs. (B) Proposed model of how mutating the polar a face residues (Asn 21 and Asn 28) in the pN1-TMDΔA to Ala alter its amphipathic assembly (white faces are polar). (C) Replication of WSNpN1-TMDΔA is restricted to 33°C. The graph displays mean viral titers ± SEM from three independent split transfections of WSNpN1-TMDΔA virus at 33°C and 37°C. (D) The indicated viral particles were isolated from the culture medium after 3 days of recovery at the indicated temperatures. The NP and M1 contents were determined by immunoblotting.