Muscleblind-Like Protein 1 (MBNL1) Antibody – Rabbit Polyclonal

This gene encodes a member of the muscleblind protein family which was initially described in Drosophila melanogaster. The encoded protein is a C3H-type zinc finger protein that modulates alternative splicing of pre-mRNAs. Muscleblind proteins bind specifically to expanded dsCUG RNA but not to normal size CUG repeats and may thereby play a role in the pathophysiology of myotonic dystrophy. Mice lacking this gene exhibited muscle abnormalities and cataracts. Several alternatively spliced transcript variants have been described but the full-length natures of only some have been determined. The different isoforms are thought to have different binding specificities and/or splicing activities. [provided by RefSeq, Sep 2015]

MBNL1: Mediates pre-mRNA alternative splicing regulation. Acts either as activator or repressor of splicing on specific pre-mRNA targets. Inhibits cardiac troponin-T (TNNT2) pre-mRNA exon inclusion but induces insulin receptor (IR) pre-mRNA exon inclusion in muscle. Antagonizes the alternative splicing activity pattern of CELF proteins. Regulates the TNNT2 exon 5 skipping through competition with U2AF2. Inhibits the formation of the spliceosome A complex on intron 4 of TNNT2 pre-mRNA. Binds to the stem-loop structure within the polypyrimidine tract of TNNT2 intron 4 during spliceosome assembly. Binds to the 5'-YGCU(U/G)Y- 3'consensus sequence. Binds to the IR RNA. Binds to expanded CUG repeat RNA, which folds into a hairpin structure containing GC base pairs and bulged, unpaired U residues. Plays a role in the pathogenesis of dystrophia myotonica type 1 (DM1). A muscular disorder characterized by myotonia, muscle wasting in the distal extremities, cataract, hypogonadism, defective endocrine functions, male baldness and cardiac arrhythmias. In muscle cells from DM1 patients, MBNL1 is sequestered by DMPK RNAs containing CUG triplet repeat expansions. MBNL1 binding is proportional to repeat length consistent with the direct correlation between the length of repeat expansion and disease severity. Belongs to the muscleblind family. 6 isoforms of the human protein are produced by alternative splicing.

Protein type: RNA splicing; RNA-binding

Chromosomal Location of Human Ortholog: 3q25

Cellular Component: centrosome; cytoplasm; nucleoplasm; nucleus; stress granule

Molecular Function: double-stranded RNA binding; metal ion binding; protein binding; RNA binding

Biological Process: embryonic limb morphogenesis; in utero embryonic development; mRNA splice site selection; myoblast differentiation; nervous system development; regulation of alternative nuclear mRNA splicing, via spliceosome; regulation of RNA splicing; RNA splicing; skeletal muscle development