RNA, U1 small nuclear 21, pseudogene (RNU1-21P)

RNU1-21P is a **pseudogene** copy related to the U1 small nuclear RNA (snRNA) gene family, specifically categorized as a variant or class I pseudogene of U1 snRNA located within chromosome 1q12-21[4][1]. The canonical U1 snRNA participates directly in the spliceosome, recognizing 5' splice sites and initiating pre-mRNA splicing, and also plays roles in preventing premature polyadenylation ("telescripting") and regulating gene expression[3][4]. In contrast, pseudogenes such as RNU1-21P arise from duplication events that typically introduce base changes, deletions, or insertions, rendering them *non-functional for protein or snRNA synthesis*, though some may still be transcribed[4][1]. Recent evidence has shown that certain U1 snRNA pseudogenes can produce variant non-coding RNAs that may be differentially expressed in specific cell types, such as stem cells and HeLa cells, and can form ribonucleoprotein (RNP) complexes[4]. These variant RNAs may have subtle regulatory influences on gene expression, but **RNU1-21P itself is not a validated protein, RNA, or enzyme target.** It is not considered a therapeutic target, receptor, enzyme, transporter, or druggable entity, and no drugs, biomarkers, or safety concerns are currently associated with it[1][4]. Therefore, listing RNU1-21P as a drug target is incorrect, and it should be catalogued as a pseudogene with possible, but largely unconfirmed, roles as a non-coding RNA[4][1].

Other names

RNU1-21PU1 snRNA class I pseudogenevariant U1 snRNAvU1 snRNA