Myoblast city (Mbc) is the ''

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (the taxonomic order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the " vinegar fly" or "pomace fly". Starting with ...

ortholog Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a s ...

of the mammalian protein

Dock180 Dock180, (Dedicator of cytokinesis) also known as DOCK1, is a large (~180 kDa) protein involved in intracellular signalling networks. It is the mammalian ortholog of the '' C. elegans'' protein CED-5 and belongs to the DOCK family of Guanine n ...

. Mutant ''mbc'' embryos exhibit defects in

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

closure,

cytoskeletal The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compo ...

organization,

myogenesis Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development. Muscle fibers generally form through the fusion of precursor myoblasts into multinucleated fibers called ''myotubes''. In the early development o ...

, and

neural development The development of the nervous system, or neural development (neurodevelopment), refers to the processes that generate, shape, and reshape the nervous system of animals, from the earliest stages of embryonic development to adulthood. The fiel ...

Discovery

The Myoblast city locus was identified by

deletion mapping In genetics and especially genetic engineering, deletion mapping is a technique used to find out the mutation sites within a gene. The principle of deletion mapping involves crossing a strain which has a point mutation in a gene, with multipl ...

, using this technique researchers were able to isolate the location of the gene on the right arm of the third chromosome. During the process four recessive

alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chrom ...

of Mbc were found; ''mbc^c1, mbc^c2, mbc^c3, mbc^s4,'' all of which are lethal and the ''D. melanogaster'' embryos fail to hatch. During the first 9-10 hours of development, embryos with the mutant Mbc alleles show the same

myosin Myosins () are a superfamily of motor proteins best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. They are ATP-dependent and responsible for actin-based motility. The first myosin (M ...

expression as

wild-type The wild type (WT) is the phenotype of the typical form of a species as it occurs in nature. Originally, the wild type was conceptualized as a product of the standard "normal" allele at a locus, in contrast to that produced by a non-standard, "m ...

embryos. However, at about the 11th hour, most

myoblasts Myogenesis is the formation of skeletal muscular tissue, particularly during embryonic development. Muscle fibers generally form through the fusion of precursor myoblasts into multinucleated fibers called ''myotubes''. In the early development o ...

fail to fuse. As development progresses, some myoblasts show signs of fusion, such as elongation and having multiple nuclei; but some remain round. After 13-14 hours of development, most cells in mutant embryos that failed to fuse lose myosin expression.

References

External links

* Insect proteins Drosophila melanogaster genes {{protein-stub