Immunity-related GTPases (IRG) (also known as p47 GTPases) are a
family of GTPase proteins found in vertebrates, which play
critical roles in mediating innate resistance to intracellular
pathogens. IRG genes have been found in a number of mammals and
lower species including mice, rats, zebrafish and humans. Most
of the mouse genes contain interferon-stimulated response
elements which mediate transcriptional activation by IFNs. In
humans, only two IRG genes have been found: human IRGC encodes a
full-length IRG protein that, like the mouse homologue, is
constitutively expressed in testis, while human IRGM encodes a
considerably truncated protein that is constitutively expressed
in cultured cells including some macrophage cell lines. As the
two human genes IRGC and IRGM are not subject to IFN control, it
has been suggested that the host resistance mechanism supported
by IRG proteins in the mouse is lacking in humans. Two isoforms
of IRGC are known to exist; this antibody will recognize both
isoforms. Additional