C-terminal deadenylase domain of nocturnin and related domains
This subfamily contains the C-terminal catalytic domain of the deadenylase, nocturnin, and related domains. Nocturnin is a poly(A)-specific 3' exonuclease that specifically degrades the 3' poly(A) tail of RNA in a process known as deadenylation. This nuclease activity is manganese dependent. Nocturnin is expressed in the cytoplasm of Xenopus laevis retinal photoreceptor cells in a rhythmic fashion, and it has been proposed that it participates in posttranscriptional regulation of the circadian clock or its outputs, and that the mRNA target(s) of this deadenylase are circadian clock-related. In mouse, the nocturnin gene, mNoc, is expressed in a circadian pattern in a range of tissues including retina, spleen, heart, kidney, and liver. It is highly expressed in bone-marrow stromal cells, adipocytes and hepatocytes. In mammals, nocturnin plays a role in regulating mesenchymal stem-cell lineage allocation, perhaps through regulating PPAR-gamma (peroxisome proliferator-activated receptor-gamma) nuclear translocation. This subfamily belongs to the large EEP (exonuclease/endonuclease/phosphatase) superfamily that contains functionally diverse enzymes that share a common catalytic mechanism of cleaving phosphodiester bonds.
Comment:based on similarity to human CCR4-NOT transcription complex subunit 6-like (CNOT6L) and other EEP superfamily members with structure; highly conserved in the EEP superfamily
Jiyao W et al.(2023). "The conserved domain database in 2023.",