. Author manuscript; available in PMC: 2012 Jul 1.

Published in final edited form as: Infect Genet Evol. 2011 Mar 5;11(5):803–811. doi: 10.1016/j.meegid.2011.02.021

Table 1. The eight segments of Influenza A, coding eleven proteins, their lengths and functions.

Segment	Size(nt)	Protein	Function
1 (PB2)	2,341	Polymerase Basic 2	Transcriptase: cap binding
2 (PB1)	2,341	Polymerase Basic 1	Transcriptase: elongation
2 (PB1)	2,341	PB1-F2 (Frame 2)	Virulence
3 (PA)	2,233	Polymerase acidic	Transcriptase: protease activity
4 (HA)	1,778	Hemaggluttinin	Binding the virus to the host cell
5 (NP)	1,565	Nucleoprotein	RNA binding; part of transcriptase complex
6 (NA)	1,413	Neuraminidase	Release of mature virions from host cell
7 (M or MP)	1,027	M1, Matrix protein 1	Component of viral envelope
7 (M or MP)	1,027	M2, Matrix protein 2	Integral membrane protein: ion channel
8 (NS)	890	NS 1(Non-structural 1)	Counters interferon, a product of the host immune system
8 (NS)	890	NS2/NEP (Non-structural 2/Nuclear Export Protein)	Effects on cellular RNA transport from the host cell nucleus to the cytoplasm, splicing, translation