Interferons (IFNs) are cytokines that regulate host resistance against
infections by exerting antimicrobial, immunomodulatory and cell growth
regulatory functions. Following their binding to specific cell surface
receptors, they induce the expression of a defined set of genes that elicit a
number of cellular responses. The HIN-200 (hematopoietic interferon-inducible
nuclear proteins with a 200-amino-acid repeat) gene family found on human and
mouse chromosome 1 is positively regulated by INFs. The murine HIN-200 gene
family consists of at least four members designated 202, 203, 204, and D3,
while the human HIN-200 family members include IFI16, the myeloid nuclear
differentiation antigen (MNDA), and AIM-2 (absent in melanoma 2). All proteins
encoded by these genes translocate to the nucleus following induction of
expression by INFs. HIN-200 proteins play a role in modulating cell growth and
perhaps in vivo differentiation. Some family members are transcriptional
regulators, acting either directly by binding DNA or indirectly by modulating
the function of other cellular transcription factors. They are hydrophilic
proteins lacking signal sequences and transmembrane region. All the proteins
belonging to the HIN-200 family contain one or two 200 amino acid long
conserved motifs, designated as the type A and type B domains, in addition to
other regions that are different or missing among the various family members.
These 200-amino-acid regions are unique to the HIN-200 proteins and contain no
known functional motifs that could provide some clue to their physiological
relevance. However, there are stretches of amino acids, such as the sequence
MFHATVAT, that exhibit almost complete identity across the A and B domains of
all family members. Altough the function of the HIN-200 domains A and B is not
known, it has been shown that the inhibition of cell growth by some HIN-200
proteins requires both domains
[4][3][2][1].
The profile we developed covers the entire HIN-200 domain.