Involved in intron recognition and spliceosome assembly. Binds probably to multiple 5'-GAAG-3' repeats found in its third intron, suggesting autoregulation of alternative splicing (PubMed:22913769). May be necessary for accurate splicing of the 3' region of introns. Component of the spliceosome. Interacts with SNRNP35, CYP59 and RS2Z33. A number of isoforms are produced. According to EST sequences. No effect on alternative splicing, due to the redundancy with SCL33. Scl33 and scl30a double mutant shows altered splicing. The splicing pattern of the pre-mRNA is regulated in a tissue-specific manner and by development, and changes in response to various types of abiotic stresses. Belongs to the splicing factor SR family. SCL subfamily.