[Detailed analyses of mutations affecting structural formation of neuromuscular synapses in Drosophila melanogaster] [Elektronische Ressource] / Mohiddin Lone

Andreas Prokop

Sujets

• Biologie

Informations

• Publié par: johannes_gutenberg-universitat_mainz
• Publié le: 01 janvier 2006
• Nombre de lectures: 14
• Langue: English
• Poids de l'ouvrage: 14 Mo

Extrait

Mohiddin Lone

Index I
CHAPTER INDEX

1 introduction
1
1.1 The importance and nature of synapses
2
1.2 Mechanisms underlying the formation of synaptic contacts
3
1.3 The choice of Drosophila as a model system
1.3.1. General possibilities of Drosophila as a model system 3
1.3.2. The idea of P-elements and mutant screens 5
1.3.3. Why looking at the embryonic NMJ? 8
1.3.4. Some insights into the development of the Drosophila NMJ 9
13
1.4. Work leading on to this project
14
1.5. Objectives of this work and summary of outcome

15 Materials and methods
15
2.1 Fly genetics and cell biology
2.1.1. Stock maintenance 15
2.1.2 Fly Stocks 15
2.1.3 Virgin collection and genetic crosses 16
2.1.4 Embryo collection 17
2.1.5 Balancing the mutant stocks over green-balancer 17
2.1.6 Whole mount embryo preparation for in-situ hybridisation or antibody 17
staining
2.1.7 Dissection of embryos and larvae 17
2.1.7.1 Dissection of early stage embryos 17
2.1.7.2 Dissection of stage 17 embryos 18
2.1.7.3 Dissection of stage 17 CNS 19
2.1.7.4. Dissection of third instar larvae 19
2.1.8 Antibody staining of the dissected animals 19
2.1.8.1 Fluorescence staining 20
2.1.8.2 Biotin Staining 20
2.1.9 Mounting of preparations 20
2.1.10 Synaptic markers 20
2.1.11 List of Primary and secondary antibodies used during this studies 21
2.1.12 Analysis of embryos and documentation 21
2.1.13 Measurement of different parameters of synaptic phenotype 22
2.1.14 In- situ hybridisation of whole mount embryos 22
2.1.15 Determination of the insertion chromosomes of transgenic flies 23
Index II
24
2.2 Molecular Biology
2.2.1 Sterilisation of solutions and glassware 24
2.2.2 E.coli culture 24
2.2.3 DNA quantification. and purification 24
2.2.4 Optical density (OD) of Bacterial cultures 24
2.2.5 Preperation of Competent cells 24
2.2.5.1 Determination of cell transformation competence 25
2.2.6 Transformation of E.coli competent cells 25
2.2.7 Processing of DGRC clones
2.2.8 Miniprep Plasmid DNA purification 26
2.2.9 Restriction enzyme digestion 26
2.2.10 Dephosphorylation of linearised DNA 26
2.2.11 Generation of Primers 26
2.2.12 Polymerase Chain Reaction 27
2.2.12.1 Single Colony PCR 27
2.2.13 Agarose gel electrophoresis 28
2.2.14 Extraction of DNA from agarose gel 28
2.2.15 Ligation of DNA molecules 28
2.2.16 Ethanol precipitation of DNA 29
2.2.17 Sequencing 29
2.2.18 Generation of digoxygenin (DIG) labelled DNA probe 30
2.2.19 Generation of Digoxygenin (DIG) labelled RNA probe 30
2.2.19.1 Labelling of probes 30
2.2.19.2 Precipitation of the RNA probe 30
2.2.20 Dot blot to asses the labelling success of digoxygenin labelled DNA 31
probes
2.2.21 RNA gel electrophoresis 31
32
2.3 Protein Expression and purification
2.3.1 GST fusion products 32
2.3.1.1 Cloning of GST fusion constructs 32
2.3.1.2 Test expression of GST fusion products 32
2.3.1.3 Large scale expression of GST-fusion products 32
2.3.1.4 Purification of GST-fusion products 33
2.3.2 His-tag constructs 33
2.3.2.1 Cloning of His-tag fusion constructs 33
2.3.2.2 Test expression of His-tag fusion products 33
2.3.2.3 Large scale expression of His-tag fusion products 34
2.3.2.4 Purification of His-tag fusion products 34
2.3.3 Protein refolding 34
2.3.4 Thrombin digestion 34
2.3.5 SDS-Polyacrylamide gel electrophoresis (PAGE) 35 Index III


36 Results

3.1 Morphological analysis of homozygous mutant fly strains 36
3.1.1 Strategy for the morphological analysis of mutant embryos 36
3.1.2. NMJ phenotypes of homozygous mutant embryos 37
3.1.3 Selection of mutant strains for further investigation 38

3.2. Complementation mapping of gene loci 39
3.2.1 The strategy 39
3.2.2 Complementation mapping of mutant fly strain 0094-13, 1227-10, 0010-
40
12, 0066-40, 0287-07 and 1151-12
P13.2.2.1 Complementation mapping of insertion 0094-13 (wah) 40
3.2.2.2 Complemeaof insertion 1227-10 43
3.2.2.3 Complementation mapping of insertion 0010-12 46
3.2.2.4 Complemeaof insertion 0066-40 49
3.2.2.5 Complementation mapping of insertion 0287-07 52
3.2.2.6 Complemeaof insertion 1151-12 54
3.2.3. Complementation mapping of insertion 1107-02. 54
3.2.3.1 Initial complementation mapping of insertion 1107-02 54
3.2.3.2 Chromosomal separation of the P-insertion at 75A and 76E 55
3.2.3.3 Precise mapping of insertion 1107-02 57
3.2.4 Complementation mapping of insertion 0242-41 59
3.2.4.1 Initial complementation mapping of insertion 0242-41 59
3.2.4.2 Precise mapping of 0242-41 61
3.2.5 Selection of mutant fly strains for further investigation 63


3.3 Analysis of 0066-40/castor 64
3.3.1 Confirmation of castor as the gene affected by the 0066-40 insertion 64
3.3.2. 0066-40 displays increased number of Q/ motorneurons 65
3.3.3. Increased pre-synaptic area is not well compensated by the post-synaptic
65
muscles


3.4 Analysis of 0242-41/eIF4AIII 68
3.4.1. The phenotype is specific to Neuromuscular terminals 68
3.4.2. Dlg accumulates in mutant NMJs 68
3.4.3. Pre- or postsynaptic overexpression of Dlg causes no obvious NMJ 69
phenotype
3.4.4 Synaptic phenotype of eIF4AIII is suppressed in dlg mutant background 72

3.5 Analysis of cG4699/waharan
73 Index IV
3.5.1. In silico analyses 75
3.5.2. Gene expression analysis via in situ RNA hybridisation 78
3.5.3. Analysis with specific RNA interference 81
3.5.3.1. Pre- and postsynaptic requirement of wah 81
3.5.3.2. Requirement of wah in larval neurons 84
3.5.3.3. Requirement of wah in wing imaginal discs 85
3.5.4. Addressing the molecular function of Wah 88
3.5.4.1. Loss of wah function induces accumulation of polyubiquitinated
88
proteins
3.5.4.2. wah mutant phenotypes can be phenocopied via knock-down of
93
proteasome function
3.5.4.3. Attempts to link Wah function to ubiquitin-regulated signalling
96
pathways involved in NMJ growth regulation
3.5.5. Generation of transgenic fly strains for the targeted expression of wah 99
3.5.5.1. HA-wah localises in neuronal cell body, somata and the boutons 102
3.5.6. Protein purification for antibody production and biochemical assays 102
3.5.6.1. General considerations 102
3.5.6.2. GST-fusion constructs 104
3.5.6.3. His-tag Fusion constructs 105

109Discussion
4.1. Some novel genes involved in Drosophila NMJ formation were discovered in
109this screen
4.2. Is CG5567/4-Nitrophenylphosphatase a good candidate gene for further
investigation? 112
4.3. Translational regulation of size at the newly forming embryonic NMJ 112
4.3.1. Nature of the gene 112
4.3.2. Potential mechanism of eIF4AIII at the developing NMJ 114
4.4. Waharan represents a novel gene potentially involved in ubiquitin-mediated 116
protein trafficking
4.4.1. Is wah the gene in question? 116
4.4.2. Spatio-temporal requirement of wah during development 117
4.4.3. The molecular mechanism of Wah function 118
4.4.4. Potential genetic interactions of wah 119


Summary 123


Appendix I 125
6.1 Different strategies to generate probes for in situ hybridisation analyses of wah 125
6.2 Cloning of non-tagged construct in to the expression vector pUAST 128
6.3 Cloning of HA-tagged construct in to expression vector pUAST 131
6.4 Domain prediction for wah 133
6.5 Molecular mapping data for the selected mutants 134Index V


143Appendix II
7.1 Chemicals 143
7.2 Kit-systems 143
7.3 Enzymes and buffers 143
7.3.1 Restriction Enzymes 143
7.3.2 Other Enzymes 143
7.4 Equipment 144
7.5 Buffers, Solutions and Media 145
7.6 Fixative Solutions 147
7.7 Dissection Tools 147
7.7.1 Sharpened tungsten wires 147
7.7.2 Sylgard 147
7.7.3 Dissection glass needles 147
7.8 Vectors 148
7.9 Oligonucleotides 149
7.10 DNA/protein markers and quantifying standards 151


Refrences
152
Index VI
FIGURE INDEX

Fig. 2.1 Localisation of NMJs, their visualisation and characterisation with 7
different markers.

Fig. 3.1 Graphic representation of genetic complementation test. 38

Fig. 3.2 Over-grown NMJ phe