Muscleblind (mbl) Antibody – Mouse Monoclonal

Muscleblind was originally isolated following studies of Drosophila, since inactivation of the muscleblind (mbl) gene in this species resulted in defects the development of muscles and the visual system (1). The Drosophila Muscleblind protein contains 4 so called Zn-CCCH Motifs (a.k.a. Cys3His or C3H motifs), members of the zinc finger family of nucleic acid binding motifs. The Zn-CCCH motifs are about 26 amino-acids long, co-ordinate one zinc ion and bind RNA. Human homologues of the single Drosophila muscleblind gene were discovered from cDNA and genomic sequencing, but were also discovered as a result of experiments aimed at finding proteins which bind to polynucleotide repeated sequences. Several important human diseases are associated with expansion of polynucleotide sequences, in most cases trinucleotide repeats. Myotonic dystrophy (DM1) is one of these diseases, and is associated with increases in the number of CTG repeats in the 3' UTR of the gene encoding myotonin (a.k.a. DM Kinase, DMK or myotonin-Protein Kinase), a ser/thr kinase expressed specifically in muscle. Normal humans have 5-37 tandem CTG repeats in this gene while those with myotonic dystrophy have from 50 to as many as 1,000 CTG repeats, with individuals with the most serious forms of the disease generally having the most repeats. Since the increased repeats were found in the 3' untranslated region (UTR) of the myotonin gene and so do not encode protein, it was puzzling as to how the increased number repeats caused the disease, especially since knock out of the myotonin gene has a relatively mild phenotype (2, 3). One theory is that the repeated sequences sequester important RNA binding and processing proteins and hence reduced the efficiency of RNA processing which would have a generally deleterious effect. To test this theory Miller et al. (4) looked for proteins that would bind specifically to the product of genomic CTG repeats in the 3' UTR, double stranded CUG RNA repeats. They found several which they named EXP proteins, for triplet repeat expansion dsRNA-binding proteins. These proteins were then identified as the mammalian homologues of the Drosophila Muscleblind protein. Mammalian genomes contain three muscleblind-like proteins, generally referred to as MBNL1, MBNL2 and MBNL3 (see below for other names), and all three were found to associate with long double stranded CUG RNA repeats. In situ hybridization studies in mouse show that all three genes are widely expressed especially in development and show significant overlap with myotonin expression (5). Recent studies show that transgenic knock out of MBNL1 in mice results in a phenotype similar to that of myotonic dystrophy, and also reduced efficiency of mRNA processing similar to those seen in this disease, both observations supporting the RNA sequestration theory (6). Although the exact function of Muscleblind proteins is not known, this and other evidence suggests that they have a role in splice site selection (6).

Small volumes of anti-mbl antibody vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. If necessary, briefly centrifuge the vial on a tabletop centrifuge to dislodge any liquid in the container`s cap. Certain products may require to ship with dry ice and additional dry ice fee may apply.

MBS649930 is an antibody targeting mbl. Also known as Muscleblind (MBNL, MBNL1, MBNL2, MBNL3). Reactive in Human, Mouse, Rat. Host: Mouse.