The biological activities of interferons (IFNs) are mediated by IFN-induced
proteins. One family is encoded by several structurally related genes loca
ted on murine chromosome 1 (Ifi 200 cluster) and three homologous genes (MN
DA, IFI 16 and AIM2) located on human chromosome 1 as well, within a linkag
e group highly conserved between mouse and human. All the proteins of this
family contain at least one copy of a conserved 200 amino acid domain, in a
ddition to other regions that are different or missing among the various fa
mily members. Conservation of the 200 amino acid segment, therefore, may be
responsible for a common function, while individually expressed domains ma
y afford other tissue- or cell-specific functions. The data available demon
strate that at least two members of the Ifi 200 protein family, p202 and p2
04, inhibit cell proliferation in vitro. Moreover, high constitutive levels
of p204 expression impair normal embryo development in transgenic animals.
Here, we will review the principal features of murine and human proteins b
elonging to this family and their function in the cell growth-regulatory ac
tivities mediated by IFNs. (C) Societe francaise de biochimie et biologie m
oleculaire/Elsevier, Paris.