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RAFIQI, ABDUL MATTEEN

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ABDUL MATTEEN
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RAFIQI
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Author: Schmidt-Ott, Urs ×

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Now showing 1 - 8 of 8
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    Megaselia abdita: cuticle preparation from injected embryos.
    (2011-04-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
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    The scuttle fly Megaselia abdita (Phoridae): a link between Drosophila and Mosquito development.
    (2011-04-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
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    BMP-dependent serosa and amnion specification in the scuttle fly Megaselia abdita
    (2012-09-15T00:00:00Z) Rafiqi, ABDUL MATTEEN; Park, Chee-Hyurng; Kwan, Chun Wai; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
    Bone morphogenetic protein (BMP) signaling is an essential factor in dorsoventral patterning of animal embryos but how BMP signaling evolved with fundamental changes in dorsoventral tissue differentiation is unclear. Flies experienced an evolutionary reduction of extra-embryonic tissue types from two (amniotic and serosal tissue) to one (amnionserosal tissue). BMP-dependent amnioserosa specification has been studied in Drosophila melanogaster. However, the mechanisms of serosal and amniotic tissue specification in less diverged flies remain unknown. To better understand potential evolutionary links between BMP signaling and extra-embryonic tissue specification, we examined the activity profile and function of BMP signaling in serosa and amnion patterning of the scuttle fly Megaselia abdita (Phoridae) and compared the BMP activity profiles between M. abdita and D. melanogaster. In blastoderm embryos of both species, BMP activity peaked at the dorsal midline. However, at the beginning of gastrulation, peak BMP activity in M. abdita shifted towards prospective amnion tissue. This transition correlated with the first signs of amnion differentiation laterally adjacent to the serosa anlage. Marker-assisted analysis of six BMP signaling components (dpp, gbb, scw, tkv, sax, sog) by RNA interference revealed that both serosa and amnion specification of M. abdita are dependent on BMP activity. Conversely, BMP gain-of-function experiments caused sharpened expression boundaries of extra-embryonic target genes indicative of positive feedback. We propose that changes in the BMP activity profile at the beginning of gastrulation might have contributed to the reduction of extra-embryonic tissue types during the radiation of cyclorrhaphan flies.
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    Megaselia abdita: culturing and egg collection.
    (2011-04-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
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    Megaselia abdita: fixing and devitellinizing embryos.
    (2011-04-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
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    Postgastrular zen expression is required to develop distinct amniotic and serosal epithelia in the scuttle fly Megaselia
    (2010-05-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
    The amnioserosa is an extraembryonic epithelium that evolved in higher cyclorrhaphan flies from distinct serosal and amniotic epithelia. The underlying genetic mechanism of this evolutionary transition is unknown. Amnioserosa development of Drosophila correlates with novel expression characteristics of the homeobox gene zerknullt (zen), including a broad zen expression domain in the syncytial blastoderm and the complete absence of postgastrular zen expression. Here we examine the functional significance of these features by altering the activity profile of zen in Megaselia (a lower cyclorrhaphan fly with distinct serosal and amniotic epithelia) and Drosophila, and by examining in Megaselia the function of u-shaped group (ush-group) genes, which in Drosophila maintain the amnioserosa after gastrulation when zen is no longer expressed. In Megaselia, loss of postgastrular zen expression abrogates serosa development but allows amnion development. Ectopic expression of zen in early Megaselia embryos allows serosa formation but perturbs amnion development. Megaselia homologues of u-shaped group genes are not essential for serosa formation but mediate germband retraction and dorsal closure. Finally, ectopic postgastrular zen expression in Drosophila causes an enlargement of amnioserosa cells and interferes with the morphogenetic functions of the amnioserosa. Our results suggest that the origin of the amnioserosa involved the loss of postgastrular zen expression from extraembryonic tissue, that the early broad expression domain of Drosophila zen evolved afterwards, and that the ush-group genes ancestrally played a role in morphogenetic functions of the amnion. (C) 2010 Elsevier Inc. All rights reserved.
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    Megaselia abdita: preparing embryos for injection.
    (2011-04-01T00:00:00Z) Rafiqi, ABDUL MATTEEN; Lemke, Steffen; Schmidt-Ott, Urs; RAFIQI, ABDUL MATTEEN
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    Hox3/zen and the Evolution of Extraembryonic Epithelia in Insects
    (2010-01-01T00:00:00Z) Schmidt-Ott, Urs; Rafiqi, ABDUL MATTEEN; Lemke, Steffen; RAFIQI, ABDUL MATTEEN
    Insects have undergone dramatic evolutionary changes in extraembryonic development, which correlate with changes in the expression of the class-3 Hox gene zen. Here, we review the evolution of this gene in insects and point out how changes in zen expression may have affected extraembryonic development at the morphological and the genetic level.