Recognition of the intron 5'-splice site by components of the assembling spliceosome.

Selection of a splice site by components of the assembling spliceosome.

The directed movement of RNA from the nucleus to the cytoplasm.

Any process involved in forming the mature 3' end of an mRNA molecule.

The process of generating multiple mRNA molecules from a given set of exons by differential use of exons from the primary transcript(s) to form multiple mature mRNAs that vary in their exon composition.

A membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some species, or in specialized cell types, RNA metabolism or DNA replication may be absent.

A discrete extra-nucleolar subnuclear domain, 20-50 in number, in which splicing factors are seen to be localized by immunofluorescence microscopy.

That part of the nuclear content other than the chromosomes or the nucleolus.

A membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing. In some species, or in specialized cell types, RNA metabolism or DNA replication may be absent.

All of the contents of a cell excluding the plasma membrane and nucleus, but including other subcellular structures.