Ruth Lehmann New York University/Howard Hughes … York University/Howard Hughes Medical Institute...
Transcript of Ruth Lehmann New York University/Howard Hughes … York University/Howard Hughes Medical Institute...
Development in Drosophila
Ruth Lehmann New York University/Howard Hughes Medical Institute
Model Organisms and InnovativeApproaches in Developmental
BiologyJuquehy, Brazil-2005
Practical session:Ruth Lehmann
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Overview of the Stages of Development
Yellow: germ cells; green mesoderm,VF ventral furrow, redmidgut (PMG and AMG anterior and posterior midgut),light blue foregut and hindgut, dark blue neuroblast, purplenervous system, pv proventriculus, go, gonad, vnc: ventralnerve cord, sg salivary gland, br brain
From V. Hartenstein Atlas of DrosophilaCSH press
Maternal effect genes:• Bicoid transcription factor
localized to anterior • Nanos translational repressor
localized to posterior• Torso receptor tyrosine kinase
activated at anterior and posterior termini• Dorsal transcription factor
localized to ventral nuclei
Three maternal gene systems control AP patterning
Anterior Posterior TerminalHead/acronthorax
abdomen
telson
abdomen
telson
telson
thorax
abdomen
head
bicoid nanos torso
Head/acron
thorax
telson
Head/acron
thorax
abdomen
telson
Maternal effect genes:
•Observe bicoid and nanos RNA localizationMethod: RNA in situ hybridization, DIC optics
•Analyze gastrulation patterns of embryos from:•wildtype mutant mothers•bicoid mutant mothers•nanos mutant mothers•torso mutant mothers•“dorsal” mutant mothers•Method: Methanol/Formaldehyde fixed embryos (2 + 0-2hrs AEL) DIC optics
Germ cell formation1) Reduction in germ cell number in embryos from tudor mutantmothers germ cells are visualized by Vasa antibody staining
2) Transcriptional derpression of tll and slam in embryos from pgcmutant mothers tll and slam RNA in situ hybridization
Method: RNA in situ hybridization, DIC optics
Oskar organizes germ plasm
Osk-/-
No germplasm/No germ cells
4X 0sk+
More germ plasm/ More germ cells
Osk-bcd3’UTR
Wild type
Reviewed in Starz-Gaiano and Lehmann (2001) Mech Dev. 105, 5-18
germ cellsposterior midgutsomatic gonadal precursors
Germ cell migration in Drosophila
Migration on posterior midgut
Attachment to gonadal mesoderm
Migration through posterior midgut
Gastrulation Germband retraction
Line formation
Formation
Gonad coalescence
aVasa
St 5
St 8 St 12
St 10
St 11
St 10/11
St 13
St 14