The @entity1 thyroid hormone receptor gene @entity21126 gives rise to two mRNAs that code for distinct isoforms, TRalpha1 and TRalpha2, with antagonistic functions. Alternative processing of these mRNAs involves the mutually exclusive use of a TRalpha1-specific polyadenylation site or TRalpha2-specific 5' splice site. A previous investigation of @entity22910 minigene expression defined a critical role for the TRalpha2 5' splice site in directing alternative processing. Mutational analysis reported here shows that @entity10043 residues within a highly conserved intronic element, SEa2, enhance splicing of TRalpha2 in vitro as well as in vivo. Although SEalpha2 is located within the intron of TRalpha2 mRNA, it activates splicing of a heterologous dsx pre-mRNA when located in the downstream exon. Competition with wild-type and mutant RNAs indicates that SEalpha2 functions by binding trans-acting factors in HeLa nuclear extract. Protein-RNA crosslinking identifies several proteins, including @entity19593 / @entity19593 and @entity68094 , that bind specifically to SEalpha2. SEalpha2 also includes an element resembling a 5' splice site consensus sequence that is critical for splicing enhancer activity. Mutations within this pseudo-5' splice site sequence have a dramatic effect on splicing and protein binding. Thus SEa2 and its associated factors are required for splicing of TRalpha2 pre-mRNA.

A XXXX -rich intronic element enhances alternative splicing of thyroid hormone receptor mRNA.

@entity1 :: ('9606', 'Species') :: ['mammalian'] @entity21126 :: ('7067', 'Gene') :: ['c-erbAalpha'] @entity10043 :: ('MESH:C030985', 'Chemical') :: ['purine'] @entity19593 :: ('6426', 'Gene') :: ['ASF', 'SF2'] @entity68094 :: ('3188', 'Gene') :: ['hnRNP H'] @entity22910 :: ('6955', 'Gene') :: ['TRalpha']
@entity10043 :: (MESH:C030985,Chemical) :: ['purine']
