Invert dev - new Flashcards
Describe complementation analysis and when it might be used.
- When used: To see if two seperate mutant organisms with same phenotype have mutation on same gene.
Process:
- cross mutant A with mutant B
- If offspring are wild-type:
- mutations of different genes –> complementary
- If offspring are mutant phenotype:
- mutations on same gene –> not complementary
Explain the difference between regulative and mosaic development
- Regulative development:
- Cell will develop according to signals from cells surrounding it, is not fated to become a specific type of cell.
- Mosaic development:
- Cell is fated to become a specific cell type. C. elegans is like this
How does sperm promote posterior cell fate in C. elegans?
The sperm provides the polarity cue, causing the polarization of PAR-2 and PAR-3.
- What are SynMuv genes?
- Where are they located?
- How many classes of them exist and why is this important?
- What is their function in terms of VPCs?
- How do they mostly regulate?
-
What are SynMuv genes?
- Synthetic Multivulval genes
-
Where are they located?
- located in Hyp7 epidermis rather than VPCs
-
How many classes of them exist and why is this important?
- Class A and B
- Are functionally redundent, so both have to be mutated to have an effect
-
What is their function in terms of VPCs?
- prevent inappropriate lin-3 expression in the hyp7
-
How do they mostly regulate?
- are epigenetic regulators controlling transcription
What role does lateral inhibition play in VPC patterning?
- Inductive signal tells P5.p, P6.p and P7.p to become 1 and 2 cells.
- Is strongest with P6.p, so it becomes 1 cell first
- 1 cells send out signal telling cells next to them not to become 2 cells
What is lin-12 and what happens in case of a lin-12(lf) mutation?
- Encodes a notch-like receptor important in lateral inhibition
- In case of lin-12(lf), all 1 and 2 VPCs will become 1 VPCs
List the 5 vulval development steps
- generation of VPCs
- Vulval precursor patterning
- generation of adult cells
- Anchor cell invasion
- Morphogenesis of vulva
Describe the basic role of PAR proteins
- Ensure taht first embryonic division is asymmetric
- Can regulate localization patterns of each other
- Activities of Par proteins ensure asymmetric partitioning of P-granules and cell fate determinants like SKN-1
Role of PIE-1
- essential regulator of germ cell fates
- can inhibit mRNA transcription to block somatic development
- prevents P2 from becoming EMS
- encodes CCCH zinc finger protein that is partitioned into P1, P2, P3, P4
- Is required for expression of NOS-2 which promotes primordial germ development
- PIE-1 remaining in anterior blastomere is degraded, requiring ZIF-1
Role of ZIF-1
- Is SOCS-box protein
- interacts with different proteins that are required for CCCH finger protein degredation
- Segregation of germ plasm involves both stabilization of germline proteins in germ line and cullin-dependent degredation in the soma
Describe function of Mex5/6
- Function to establish Soma/Germline asymmetry in early C. elegans embryos
- Regulate cell fate by regulating mRNA translation, incluidng zif-1 mRNA
- localiztion regultated by PAR-1
- diffuses faster in posterior (doesn’t stay as long)
- likely that Mex-5 function is to inhibit anterior expression of germline proteins
Describe the role of Wnt signaling in C. elegans embryonic development
- Wnt ligand binds LRP and Frizzled to start signaling pathway
- Lit-1(ts) permits wide scale blockage of Wnt signaling
- Wnt signaling polarizes an early C. elegans blastomere to distinguish endoderm from mesoderm
- Regulates orientation of cell division
- a posterior center establishes and maintains polarity of C. elegans embryo by Wnt-dependent signaling
- posterior cells assumer anterior fates when Wnt signaling is blocked
Give a brief description of heterochronics and heterochrony
what are Alae?
- Heterochrony: developmental change in timing or rate of events, leading to changes in size and shape
- Alae: adult specific ridges in cuticle on worm (is a way to say that it is an adult)
- A hierarchy of genes control larva to adult development in C. elegans
Describe role of Lin-14 and 2 types of mutations
- Role: works in early stages of development to inhibit lin-29 and stop if from flipping switch to go from larval to adult form
mutations:
- Retarded: semidominant mutant, is seen in T-lineage
- in L2 stage, T.ap generates a cell division pattern and ascendent cell types similar to those normally generated during L1 by T cell.
- Precocious: in recessive lin-14 mutant
- T cell precociously generates cell division pattern normally generated during L2 by T.ap
Function of lin-4 and how it works
- Encodes small RNAs with antisense complimentarity to 3’ UTR of lin-14
- inhibits lin-14 translation
- Mediates temporal pattern formation in C. elegans by creating temporal gradient in lin-14
Describe role and method of let-7
- regulates temporal timing in C. elegans
- transition from late larva to adult requires let-7 RNA
- binds to 3’UTRs of target mRNAs
Describe role of daf-12
- Encodes a nuclear receptor that regulates the dauer diapause and development age in C. elegans
- when daf-12 is active, it inhibits activity of let-7, allowing larva to go to adult form
Describe transposable elements and how they are evolutionarily useful.
- are mobile genetic elements that are moved from one position in the genome to another
- each carries unique set of genes
- catalyzed by transposases
- useful because induce genetic variance
- diagram depicts “cut and paste” transposition
How can GFP be useful in fly genetics
Can be inserted into genome to trace cells in space and time