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Dystroglycan and mitochondrial ribosomal protein L34 regulate differentiation in the Drosophila eye.

Zhan Y, Melian NY, Pantoja M, Haines N, Ruohola-Baker H, Bourque CW, Rao Y, Carbonetto S - PLoS ONE (2010)

Bottom Line: Overexpression of DG in R cells results in a small but significant increase in their size.We conclude that DG does not affect neuronal commitment but functions R cell autonomously to regulate neuronal elongation during differentiation in the pupa.We discuss these findings in view of recent work implicating DG as a regulator of cell metabolism and its genetic interaction with mRpL34, a member of a class of mitochondrial genes essential for normal metabolic function.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Neuroscience, McGill University Health Centre, Montreal, Quebec, Canada.

ABSTRACT
Mutations that diminish the function of the extracellular matrix receptor Dystroglycan (DG) result in muscular dystrophies, with associated neuronal migration defects in the brain and mental retardation e.g. Muscle Eye Brain Disease. To gain insight into the function of DG in the nervous system we initiated a study to examine its contribution to development of the eye of Drosophila melanogaster. Immuno-histochemistry showed that DG is concentrated on the apical surface of photoreceptors (R) cells during specification of cell-fate in the third instar larva and is maintained at this location through early pupal stages. In point mutations that are for DG we see abortive R cell elongation during differentiation that first appears in the pupa and results in stunted R cells in the adult. Overexpression of DG in R cells results in a small but significant increase in their size. R cell differentiation defects appear at the same stage in a deficiency line Df(2R)Dg(248) that affects Dg and the neighboring mitochondrial ribosomal gene, mRpL34. In the adult, these flies have severely disrupted R cells as well as defects in the lens and ommatidia. Expression of an mRpL34 transgene rescues much of this phenotype. We conclude that DG does not affect neuronal commitment but functions R cell autonomously to regulate neuronal elongation during differentiation in the pupa. We discuss these findings in view of recent work implicating DG as a regulator of cell metabolism and its genetic interaction with mRpL34, a member of a class of mitochondrial genes essential for normal metabolic function.

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Third instar development is not disrupted in Df(2R)Dg248 mosaics.Immunohistochemistry with antibodies to 24B10 (A, D), Elav (B, E) and Boss (Bride of Sevenless) (C, F) identify R cells in wild type (A–C) and ey/FLP induced mosaic eye imaginal discs (D–F) in the late 3rd instar larvae. 24B10 (A and D) and Elav (B and E), localize normally (A, B) in Df(2R)Dg248 deficient eye discs (D, E). Similarly Boss, which is expressed on the apical surface of R8 and necessary for formation of R7, is localized normally (C) in Df(2R)Dg248 deficient eye discs (F). Bar represents 10 µm.
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pone-0010488-g005: Third instar development is not disrupted in Df(2R)Dg248 mosaics.Immunohistochemistry with antibodies to 24B10 (A, D), Elav (B, E) and Boss (Bride of Sevenless) (C, F) identify R cells in wild type (A–C) and ey/FLP induced mosaic eye imaginal discs (D–F) in the late 3rd instar larvae. 24B10 (A and D) and Elav (B and E), localize normally (A, B) in Df(2R)Dg248 deficient eye discs (D, E). Similarly Boss, which is expressed on the apical surface of R8 and necessary for formation of R7, is localized normally (C) in Df(2R)Dg248 deficient eye discs (F). Bar represents 10 µm.

Mentions: To trace the genesis of these defects we examined 3rd instar larval eye discs. R cells are sequentially specified and recruited to form presumptive ommatidia posterior to the morphogenic furrow. Wild type ommatidia are composed of the eight R cells, each roughly occupying an equal fraction of the omatidial volume, and attached to other R cells at their lateral and apical surfaces. During pupal development the R-cells elongate as they differentiate. Using neuronal and cell polarity markers R-cell specification and morphology were examined in Df(2R)Dg248 mosaic eye discs. In third instar larvae, R cells were specified normally, as determined by 24B10 and Bride of Sevenless (Boss) staining of eye discs (Fig. 5D–F), suggesting that neither Dg nor mRpL34 are required for neural commitment. Similar results were found with flies for Dg (DgO55; Melian and Carbonetto, unpublished). We conclude that lack of Dg alone or Dg plus mRpL34 does not affect neuronal commitment that occurs in the 3rd instar larva.


Dystroglycan and mitochondrial ribosomal protein L34 regulate differentiation in the Drosophila eye.

Zhan Y, Melian NY, Pantoja M, Haines N, Ruohola-Baker H, Bourque CW, Rao Y, Carbonetto S - PLoS ONE (2010)

Third instar development is not disrupted in Df(2R)Dg248 mosaics.Immunohistochemistry with antibodies to 24B10 (A, D), Elav (B, E) and Boss (Bride of Sevenless) (C, F) identify R cells in wild type (A–C) and ey/FLP induced mosaic eye imaginal discs (D–F) in the late 3rd instar larvae. 24B10 (A and D) and Elav (B and E), localize normally (A, B) in Df(2R)Dg248 deficient eye discs (D, E). Similarly Boss, which is expressed on the apical surface of R8 and necessary for formation of R7, is localized normally (C) in Df(2R)Dg248 deficient eye discs (F). Bar represents 10 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2864756&req=5

pone-0010488-g005: Third instar development is not disrupted in Df(2R)Dg248 mosaics.Immunohistochemistry with antibodies to 24B10 (A, D), Elav (B, E) and Boss (Bride of Sevenless) (C, F) identify R cells in wild type (A–C) and ey/FLP induced mosaic eye imaginal discs (D–F) in the late 3rd instar larvae. 24B10 (A and D) and Elav (B and E), localize normally (A, B) in Df(2R)Dg248 deficient eye discs (D, E). Similarly Boss, which is expressed on the apical surface of R8 and necessary for formation of R7, is localized normally (C) in Df(2R)Dg248 deficient eye discs (F). Bar represents 10 µm.
Mentions: To trace the genesis of these defects we examined 3rd instar larval eye discs. R cells are sequentially specified and recruited to form presumptive ommatidia posterior to the morphogenic furrow. Wild type ommatidia are composed of the eight R cells, each roughly occupying an equal fraction of the omatidial volume, and attached to other R cells at their lateral and apical surfaces. During pupal development the R-cells elongate as they differentiate. Using neuronal and cell polarity markers R-cell specification and morphology were examined in Df(2R)Dg248 mosaic eye discs. In third instar larvae, R cells were specified normally, as determined by 24B10 and Bride of Sevenless (Boss) staining of eye discs (Fig. 5D–F), suggesting that neither Dg nor mRpL34 are required for neural commitment. Similar results were found with flies for Dg (DgO55; Melian and Carbonetto, unpublished). We conclude that lack of Dg alone or Dg plus mRpL34 does not affect neuronal commitment that occurs in the 3rd instar larva.

Bottom Line: Overexpression of DG in R cells results in a small but significant increase in their size.We conclude that DG does not affect neuronal commitment but functions R cell autonomously to regulate neuronal elongation during differentiation in the pupa.We discuss these findings in view of recent work implicating DG as a regulator of cell metabolism and its genetic interaction with mRpL34, a member of a class of mitochondrial genes essential for normal metabolic function.

View Article: PubMed Central - PubMed

Affiliation: Centre for Research in Neuroscience, McGill University Health Centre, Montreal, Quebec, Canada.

ABSTRACT
Mutations that diminish the function of the extracellular matrix receptor Dystroglycan (DG) result in muscular dystrophies, with associated neuronal migration defects in the brain and mental retardation e.g. Muscle Eye Brain Disease. To gain insight into the function of DG in the nervous system we initiated a study to examine its contribution to development of the eye of Drosophila melanogaster. Immuno-histochemistry showed that DG is concentrated on the apical surface of photoreceptors (R) cells during specification of cell-fate in the third instar larva and is maintained at this location through early pupal stages. In point mutations that are for DG we see abortive R cell elongation during differentiation that first appears in the pupa and results in stunted R cells in the adult. Overexpression of DG in R cells results in a small but significant increase in their size. R cell differentiation defects appear at the same stage in a deficiency line Df(2R)Dg(248) that affects Dg and the neighboring mitochondrial ribosomal gene, mRpL34. In the adult, these flies have severely disrupted R cells as well as defects in the lens and ommatidia. Expression of an mRpL34 transgene rescues much of this phenotype. We conclude that DG does not affect neuronal commitment but functions R cell autonomously to regulate neuronal elongation during differentiation in the pupa. We discuss these findings in view of recent work implicating DG as a regulator of cell metabolism and its genetic interaction with mRpL34, a member of a class of mitochondrial genes essential for normal metabolic function.

Show MeSH
Related in: MedlinePlus