Disease relevance of mbl

• Myotonic dystrophy associated expanded CUG repeat muscleblind positive ribonuclear foci are not toxic to Drosophila [1].

High impact information on mbl

• Remarkably, the EXP proteins are homologous to the Drosophila muscleblind proteins required for terminal differentiation of muscle and photoreceptor cells [2].
• As in patients, expanded CUG repeats form discrete ribonuclear foci in Drosophila muscle cells that co-localize with muscleblind [1].
• To provide further insights into muscleblind function and the pathogenesis of myotonic dystrophy, we generated Drosophila incorporating CTG repeats in the 3'-UTR of a reporter gene [1].
• We have isolated the embryonic lethal gene muscleblind (mbl) as a suppressor of the sev-svp2 eye phenotype [3].
• The muscleblind gene participates in the organization of Z-bands and epidermal attachments of Drosophila muscles and is regulated by Dmef2 [4].

Biological context of mbl

• Functional analysis of mbl, the observation that it also dominantly suppresses the sE-Jun(Asp) gain-of-function phenotype and the phenotypic similarity to mutants in the photoreceptor-specific glass gene suggest that mbl is a general factor required for photoreceptor differentiation [3].
• On the other hand, the use of distantly located DNA probes in the mbl gene allowed us to orientate the transcription unit in the chromosome [5].
• RT-PCRs with exon-specific primers downstream of exon 2 were unable to amplify products other than those expected from canonical mbl isoforms, thus indicating that no other exons were efficiently spliced downstream of exon 2 [6].
• In this review, we focus on the Muscleblind family of tissue-specific alternative splicing regulators [7].
• Muscleblind proteins bind pre-mRNA through an evolutionarily conserved tandem CCCH zinc finger domain [7].

Anatomical context of mbl

• Analysis of clones mutant for mbl during eye development shows that it is autonomously required for photoreceptor differentiation [3].

References