Lecture 31 Development Flashcards
1
Q
4 Important concepts of embryonic development
A
- Universal mechanisms of animal development
- Proteins can be substituted across species
- Inductive signaling
- Regional determination
2
Q
Unersal mechanisms of animal development use 5 pathways
A
- Receptor tyrosine kinase
- TGFB superfamily
- Wnt
- Hedgehog
- Notch
3
Q
Receptor tyrosine kinase
A
-EGF ligands
- EGF receptors
FGF, and ephrins
4
Q
TGFB superfamily
A
- TGFB ligands and receptors
- BMP (DPP) ligands and receptors
- nodal ligands
5
Q
Wnt
A
- wnt ligand and frizzled receptor
6
Q
Hedgehog
A
- hedgehog ligand and patched/smoothened receptor
7
Q
Notch
A
- Delta ligand and notch receptor
8
Q
What defines the developmental program of multicellular organisms?
A
- Regulatory DNA
- multi cellular organisms are enriched in proteins mediating cell interactions and gene regulation
9
Q
Is inductive signaling just local?
A
No it can act over great distances and affect multiple cells
10
Q
regional determination
A
- once cells are committed to form a particular structure they can be taken out of resident area and transplanted to a different region but continue to behave like they did in other cite
- thoracic vertebrae developing like thoracic even though its been moved to cervical region
11
Q
Sequential induction
A
- builds a group of different cells
- B works on A and produces C
- C works on A and. B and produces D and E
12
Q
4 essential processes by which an embryo is constructed
A
- Cell proliferation
- Cell specialization (differentiation)
- Cell interaction
- Cell movement
All 4 processes must be working to achieve particular organism
13
Q
Developmental process greatly among different species.
A
- mouse have 21 day gestational periond
- elephants have 645 day
14
Q
Patterning
A
- cells that are produced by cleavage get organized into layers and groups of cell masses through what is know as gastrulation
15
Q
Organization of cells into layers and cell masses is know as?
A
- gastrulation
16
Q
Patterning occurs in what three dimensions?
A
- Anterior - posterior
- Proximal - Distal
- Dorsal- Ventral
17
Q
Differentiation
A
- cells begin to form specific and specialized structures
18
Q
Growth
A
- cell divisions that form more cells with identical functions as the parental cells
19
Q
Paradigm of development
A
- in every species and at every level of organization, complex structures are made by repeating a few basic themes with variations
20
Q
Gastrulation is the formation of what 3 key cell layers?
A
- Ectoderm
- Mesoderm
- Endoderm
21
Q
Gastrulation
A
- infolding of cells from outer layer to inner layer
- creating clusters of cells that have specialized function
22
Q
Hensens node
A
- organizing structure of gastrulation
- acts like a zipper
23
Q
Neural crest cells
A
- embryonic cell population that is localized between the developing neural tube and the non- neural ectoderm
24
Q
Stemness
A
- neural crest cells that can give rise to multiple differentiated cells exhibit stemness
- can renew itself
25
How do neural crest cells form craniofacial structures?
- they migrate through restricted pathways to form the developing structures
26
Cell migration
`- a tightly regulated process where the NCCs receive cues such as morphogens and growth factors that restrict their movement and determine fate
27
Where do the cues for cell migration come from?
- adjacent cells
28
Neural crest cells
- move out and give rise to tissues
| - regions where they migrate are called rhombomeres
29
Different signals are giving information to ectoderm and dermomyotome
- true
30
The segmental plate mesoderm gives rise to what?
- epithelial somites
31
Epithelial somites give rise to what?
-dermamyotome and sclerotome
32
The dermamyotome gives rise to what?
- dermatome and myotome
33
The sclerotome gives rise to what?
- ribs
- vertebrae
- base of skull; some facial muscles
34
The dermatome gives rise to what?
- dermis
35
The myotome gives rise to what?
epaxial skeletal muscle and hypaxial skeletal muscle
36
Coordinate genes
regulate gap genes
37
Gap genes
- self regulate
- regulate pair rule genes
- regulate homeotic selector genes
38
Pair rule genes
- self regulate
- regulate homeotic selctor genes
- regulate segment polarity genes
39
Homeotic selector genes
- regulate other genes
40
Segment polarity genes
- regulate self
| - regulate homeotic selector genes
41
Homeosis
- replacement of one body part with another
42
Drosophila Homeotic Genes
- gene products are gene regulatory proteins
- All contain a highly conserved DNA binding homeodmain sequence 60 amino acids long
- The corresponding segment in the 180 BP DNA sequence is called a homeobox hence the name hox complex
43
Hox genes
- interspersed amongst large stretches of regulatory DNA regions
- Hox genes are expressed sequentially according to their order in the HOx complex
- Hox complex carries a permanent record of positional information (why head goes in the right spot)
- There are hundreds of other homeobox genes in the genome, but they are scattered and not clustered in complexes
44
How many hox complexes do drosophila have?
2
45
How many hox complexes do mammalia have?
4
46
T/F mouse complexes are located at 3 different chromosomes?
false (4)
47
When do the lip forms?
between 4th-7th week of pregnancy
48
When does the palate form?
between weeks 6 and 9
