interferon lambda-4; IFN-lambda-4 (IFNL4)

Function

• cytokine
• may trigger an antiviral response activating the JAK-STAT pathway & up-regulating specifically some interferon- stimulated genes
• able to prevent hepatitis C virus replication in cell cultures

Structure

• belongs to the lambda interferon family

Compartment

cytoplasm. secreted

Alternative splicing

• named isoforms=4
• additional isoforms seem to exist; however, they may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

Expression

• up-regulated by polyinosinic:polycytidylic acid (polyI:C) which mimics double-stranded hepatitis C virus

Polymorphism

• genetic variation in IFNL4 is associated with susceptibility to hepatitis C virus (HCV) infection
• a one-base insertion, introducing a frameshift at position 22, results in inactivation of the gene in a majority of the population
• this polymorphism is a good marker for predicting spontaneous HCV clearance & the response to treatment of chronic hepatitis C
• the allele producing a functional protein able to induce an antiviral response & to prevent HCV replication in cell cultures, is less frequent in human populations & is associated with impaired spontaneous clearance of HCV

More general terms

• interferon [IFN]-lambda (IFNL)

Additional terms

• interleukin-28B; IL-28B; cytokine Zcyto22; interferon lambda-3; IFN-lambda-3; interleukin-28C; IL-28C (IL28B, IFNL3, IL28C, ZCYTO22)

Database

• OMIM: https://mirror.omim.org/entry/615090
• UniProt: http://www.uniprot.org/uniprot/K9M1U5.html