DICER1 is a gene encoding an endoribonuclease critical to the generation of small noncoding regulatory RNAs.
Human DICER1 protein possesses an RNA helicase motif containing a DEXH box in its amino terminus and an RNA motif in the carboxy terminus.
DICER1, also known as helicase-MOI, is required by the RNA interference and small temporal RNA (stRNA) pathways to produce the active small RNA component that represses gene expression.
In RNA interference, the RNase-III enzyme Dicer processes exogenous double-stranded RNA into small interfering RNAs (siRNAs). siRNAs guide RNA-induced silencing complexes to cleave homologous transcripts, enabling gene-specific knock-down.
In plants, double-stranded RNA is processed into siRNA species of 21 nucleotides (nt) and 24 nt, but, unlike in nematodes, the Dicer enzymes involved in this processing have not been identified.
Additionally, in both plants and nematodes, systemic signals with RNA components convey the sequence-specific effects of RNA interference between cells.
Pathology
germline mutations of DICER1 in pleuropulmonary blastoma (PPB)
- PPBs consist of mesenchymal cells that are susceptible to malignant transformation and cysts lined by epithelial cells. In a subset of patients, overgrowth of the cysts by mesenchymal cells leads to sarcoma formation.
Expression of DICER1 protein was undetectable in the epithelial component of PPB tumors but was retained in the malignant mesenchyme (sarcoma).
References
DICER1 Mutations in Familial Pleuropulmonary Blastoma. Hill DA, Ivanovich J, Priest JR, Gurnett CA, Dehner LP, Desruisseau D, Jarzembowski JA, Wikenheiser-Brokamp KA, Suarez BK, Whelan AJ, Williams G, Bracamontes D, Messinger Y, Goodfellow PJ. Science. 2009 Jun 25. PMID: 19556464