U6atac

U6atac is a small nuclear RNA (snRNA) that serves as the RNA component of the minor (U12-type) spliceosome. It partners with U4atac to form the U4atac/U6atac di-snRNP, which, together with U5, contributes to the formation of the U4atac/U6atac/U5 tri-snRNP that catalyzes splicing of U12-type introns.

During assembly, U11 and U12 snRNPs recognize the 5' splice site and branch point of U12-type introns. The U4atac/U6atac di-snRNP joins with U5 to create the catalytic minor spliceosome, which conducts the two transesterification steps that remove the intron and ligate the exons.

U6atac is highly conserved across eukaryotes and is approximately 130 nucleotides in length. Its sequence contains conserved motifs that enable base pairing with U4atac and interactions with associated snRNP proteins, including factors that bind the 3' end of the RNA.

Biogenesis and maturation follow the general pathway of snRNAs: transcription, processing, and assembly into snRNPs in nuclear compartments, enabling participation in pre-mRNA splicing.

Clinical significance: Defects in components of the minor spliceosome, including pathways involving U6atac, have been linked to developmental disorders and diseases, highlighting the essential role of U12-type intron splicing in human gene expression.

See also: U11 snRNA, U12 snRNA, U4atac snRNA, U5 snRNA, minor spliceosome.