tRNA Splicing Endonuclease 2 (TSEN2)

SEN2 is a subunit of the tRNA splicing endonuclease, which catalyzes the removal of introns, the first step in tRNA splicing.Full-length SEN2 contains 465 amino acids and has a calculated molecular mass of 51 kD. It shares a high degree of similarity with yeast Sen2 only in the active site domain.The SEN2 variant lacking exon 8 contains 448 amino acids. Northern blot analysis detected low expression of both SEN2 transcripts in all tissues examined. Immunofluorescence microscopy of transfected HeLa cells localized both SEN2 isoforms to the nucleus. The variant lacking exon 8 was frequently found in nucleoli in dot-like structures.Additionally, the SEN2 variant lacking exon 8 is part of a complex with unique RNA endonuclease activity.