Midterm 1- Excludes Lecture 1,3,5,13 Flashcards
Compartment
boundary restricting movement of cells
Gap gene
a type of gene involved in the development of the segmented embryos of some arthropods. Gap genes are defined by the effect of a mutation in that gene, which causes the loss of contiguous body segments, resembling a gap in the normal body plan
PAL-1
caudal-like transcription factor specifying C and D fates
Holometabolous Development
a form of insect development which includes four life stages: egg, larva, pupa, and imago (or adult)
Role of B-catenin in sea urchin development
β-catenin and Otx activate expression of Pmar1 in micromeres
Pmar1 represses HesC, a repressor of micromere fate. Without micromeres there is no vegetal fate
Hox genes
!Specify parasegment! identity through the control of expression domains which work together to give rise to the unique parasegments. It does this through the production of homeobox transcription factors
Cell-autonomously specification
Cell fate develops through the localization of Determinants being asymmetrically distributed in the dividing cell
Methods of Cell fate specification
1)Autonomously
2)Cell-cell interactions
3)Cell-cell interactions through use of morphogens
SKN-1
Disables PAL-1 in the EMS cells, transcription factor specifying EMS fate
APX-1/GLP-1
Homologous to Delta/Notch pathway and signals for ABp cell fate
Relation between Bicoid, Caudaul, Nanos, and hunchback
Nanos prevents translation of hunchback mRNA in the posterior of the embryo and Biccoid prevents the translation of Caudal in the anterior and activates
zygotic hunchback
expression
Relationship between Sog, Dpp, and Tld in forming the Dorsal/ Ventral axis
Sog-Sog binds to Dpp and inactivates it
Dpp- specifies amnioserosa and dorsal ectoderm and only forms when dorsal protein is not present
Tld-cleaves Sog, leading to a peak of Dpp activity in the dorsal most region
Nurse cell
produce (among other things) mRNAs for morphogens for a-p patterning of the embryo. These mRNAs are transported and localized within the oocyte
Three levels of description and Understanding
1)Macroscopic, Descriptive-Focuses on describing the phenomenon instead of explaining it
2)Cellular, “Conceptual”-Describes the steps involved in triggering a phenomenon
3)Molecular- Describes the exact chemicals and genes necessary for an event to occur
Determination
Implies a stable change in the internal state of a cell that cannot be altered usually due to gene expressions
Special properties of C.elegans
- Soil nemotodes composed of 959 cells
- Invarient development
Draw the Bicoid and Nanos effect of Hunchback
Orginally maternal Hunchback is farily evenly spread between the Anterior and posterior but interaction with bicoid greatly increases zygotic hunchback in the anterior with the interaction of nanos disabling zygotic hunchback
Neuroblasts in Drosophila
The nervous system starts to form,
when neuroblasts delaminate from the
ventral ectoderm.
Draw the fate map and appropriate proteins involved in the first 8 cells of C.elegans
Draw the founder cell cleavage pathway with the end tissues formed
Morphogen
a substance involved in pattern formation that forms a gradient and elicits at least two different responses at different thresholds (at the same time)
Nanos localization
Localized to the Posterior Axis
Experiment that corresponds to the three levels of understanding
1)Macroscopic-Observations
2)Cellular-graft or transplant experiment
3)Molecular- gene expression experiments
How is Kruppel regulated by Hunchback
Kruppel is only activated in a specified area where hunchback is in high enough concentration to activate the gene but not high enough concentration to deactivate the gene.
Dorsal/Ventral Axis
Top and Bottom axis
How is bicoid spread throughout the embryo?
bicoid mRNA is localized to the anterior, but
Bicoid protein can diffuse
freely through the syncytium
and forms a gradient
How are EVE strips determined?
generalized activation by bcd and ubiquitous transcription factors combined with localized repression by gap genes. Each of the eight stripe borders of these four stripes is shown to be under the control of a particular gap gene expression domain.
Imaginal Disks
give rise to certain adult structures (wing, leg, eye). They are patterned during embryogenesis
Proteins involved in making the Dorsal Protein
Pipe- begins the pathway by binding to an unknown subtrate
Spatzle-Activates the Toll Receptors
Toll-Triggers the degredation of Cactus
Cactus-Binds to Dorsal and prevents it from entering the Nucleus and altering gene expression
Gastrulation
During gastrulation future endodermal and mesodermal cells move to
the inside of the embryo to form the inner cavities of the body.
Bicoid localization
Localized to the anterior axis
Regulative Development
embryos using external signals have the potential to replace missing cells
Bithorax Complex Genes
UBX, abd-A, Abd-B
Lithium treatment of sea urchins
Li treatment of sea urchin embryos causes vegetalisation. This is because Li is known to block the GSK-3 kinase, which negatively
regulates the Wnt/Wg pathway by mediating degradation of the effector β-catenin
Anterior/Posterior Axis
Front and Back axis
Germ Layers and their organs formed
1)Mesoderm-Skeleton, Muscles,kidney,heart, blood
2)Endoderm-Gut,Liver,lungs
3)Ectoderm-Skin, Nervous System
Dorsal Protein
Morphogen which helps define the ventral axis. At high concentrations it activates the twist genes and at low concentrations it activates the dpp gene
Caudal protein
responsible for the formation of abdominal structures