TSEN2

TSEN2 is one of the subunits of the tRNA splicing endonuclease. TSEN2 catalyzes the first step in RNA splicing which is the removal of introns. Mutations in TSEN2 have been associated with pontocerebellar hypoplasia type 2. A pseudogene has been identified on chromosome 4.

Full Name

TRNA Splicing Endonuclease Subunit 2

Function

Constitutes one of the two catalytic subunit of the tRNA-splicing endonuclease complex, a complex responsible for identification and cleavage of the splice sites in pre-tRNA. It cleaves pre-tRNA at the 5'- and 3'-splice sites to release the intron. The products are an intron and two tRNA half-molecules bearing 2',3'-cyclic phosphate and 5'-OH termini. There are no conserved sequences at the splice sites, but the intron is invariably located at the same site in the gene, placing the splice sites an invariant distance from the constant structural features of the tRNA body. Isoform 1 probably carries the active site for 5'-splice site cleavage. The tRNA splicing endonuclease is also involved in mRNA processing via its association with pre-mRNA 3'-end processing factors, establishing a link between pre-tRNA splicing and pre-mRNA 3'-end formation, suggesting that the endonuclease subunits function in multiple RNA-processing events. Isoform 2 is responsible for processing a yet unknown RNA substrate. The complex containing isoform 2 is not able to cleave pre-tRNAs properly, although it retains endonucleolytic activity.

Biological Process

Biological Process mRNA processing Source:UniProtKB-KW
Biological Process tRNA splicing, via endonucleolytic cleavage and ligation Source:UniProtKB1 Publication
Biological Process tRNA-type intron splice site recognition and cleavage Source:GO_Central1 Publication

Cellular Location

Nucleus
Nucleus, nucleolus
May be transiently localized in the nucleolus.

Involvement in disease

Pontocerebellar hypoplasia 2B (PCH2B):
A disorder characterized by an abnormally small cerebellum and brainstem, and progressive microcephaly from birth combined with extrapyramidal dyskinesia. Severe chorea occurs and epilepsy is frequent. There are no signs of spinal cord anterior horn cells degeneration.