FIG. 2.

Phylogenetic relationship of the IRF protein family. A neighbor-joining tree of the entire family was constructed based on alignment of protein sequences by the computer program ClustalX. Chicken (Gg), clawed toad (Xl), human (Hs), Japanese flounder (Po), mouse (Mm), quail (Cj), rat (Rn), sheep (Oa), and torafugu (Tr) IRF sequences were analyzed. The full-length sequences of the individual IRF family members and a sequence of P. olivaceus IRF-8 with an incomplete C terminus derived from the EST database entry were included (see Table 2). The four IRF subfamilies are indicated in the margins. The bootstrap confidence values shown at the nodes of the tree are based on 1,000 bootstrap replications.