The interferon-induced protein 44-like gene (i.e., IFI44L gene, also known as the GS3686, TLDC5B, and C1orf29 gene https://www.wikidata.org/wiki/Q18035986) codes for the interferon-induced protein 44-like protein (i.e., IFI44L protein). This gene is located in band 1, region 1 (see band and gene nomenclature) on the short, i.e., "p", arm of chromosome 1 (location abbreviated as 1p31.1). A closely related gene, the interferon-induced protein 44 gene (i.e. the IFI44 gene), is a paralog of the IFI44L gene (i.e., the two genes are duplicates of an ancestorial gene). The IFI44L and IFI44 proteins are composed of 452 and 444 amino acids, respectively, share 45% amino acid identity along with 60% homology at the amino acid level, and have many similar or overlapping functions and activities. This article focuses on the function and clinical significance of the IFI44L gene and the IFI44L protein that it directs to be formed.
The IFI444L gene is an interferon-stimulated gene in which type I interferons stimulate it to transcribe, i.e., make, its messenger RNA (mRNA) which in turn directs formation of the IFI44L protein. Type I interferons are cytokines which immune cells secrete in response to the accumulation of cytoplasmic DNA that occurs in microbe-infected cells, cancer cells, and cells with other types of injuries or abnormalities. Humans have 13 different type I interferon-α proteins: type I interferon-α1, -α2, - α4, -α5, -α6, -α7, -α8, - α10, -α13, - α14, -α16, -α17, -α21, and 4 other type I interferon proteins, type I interferon-β, -ε, -κ, and -Ω. These interferons bind to and stimulate the interferon-alpha/beta receptors located in a wide range of cells which when so stimulated act to promote or inhibit the inflammatory reactions associated with a various diseases and disorders including certain infections, cancers, genetic disorders, and autoimmune diseases. Diseases and disorders promoted by the type I interferons are termed interferon type I interferonopathies. Among the many genes that they influence, type I interferons stimulate cells to transcribe the IFI44L gene (see interferon-alpha/beta signaling) thereby increasing production of the IFI44L protein. Alterations in the expression of the IFI44L gene may be helpful in diagnosing and estimating the severity of various diseases and disorders and in some cases suggest that it may be targeted (i.e., stimulated or inhibited from forming IFI44L protein) to alter their development and/or progression.
