DEV BIO 3

In this image of a newborn mouse spinal cord, three transcription factors are immunolabeled that are expressed in different neuronal subtypes. What letter is the closest to the anatomical location where NEPs first generate lower motor neurons at the earlier stages of neurogenesis?

A- lower motor neurons generate from the ventral root

Spinal Muscular Atroph is a life threatening genetic disorder caused by the premature death of lower motor neurons often due mutation in the Survival Motor Neuron 1 (SMN1) gene. A new gene replacement based therapeutic has been developed using a viral vector that re-expresses SMN1. The compound Zolgensma, has recently sucessfully completed Phase 3 trials. You would like to improve the therapy by adding genes to the viral vector. Overexpression of what gene would be most likely to futher enhance lower motor neuron survival?

Bcl-2 would improve cell survival

Recent studies of postmortem samples from patients diagnosed with autism spectrum disorder noted patches of disorganized lamination in the upper layers of the cerebral cortex. The period of cortical neurogenesis in humans begins at 42 daps post-conception (dpc) and is completed by ~120 dpc. Which of the following times do you think cortical morphogeneis was most-likely effected?

~100 dpc

Which master transcription factors would most likely be expressed in a brain organoid system?

SOX2

Which master transcription factors would most likely be expressed in the mesodermal lineage?

TBX6

Which master transcription factors would most likely be expressed in the muscle lineage?

MOYD

Which master transcription factors would most likely be expressed in the germ cell lineage?

FRAGILIS

You would like to study the proliferation of neural stem cells in the early embryonic brain. Which reagents would be particularly useful for labeling cells that have recently proliferated/underwent cell division?

[3H] or BrdU

Prior to the TSP you incubate Trachemys scripta turtle eggs at a temperature that produces 100% males during the TSP. This will results in...

No effect on sex determination

You incubate Alligator missippiensis eggs at 33C during the TSP. What do you predict the level of aromatase activity?

10% lowest level of activity

If there is a mutation in the male specific exon of sex-lethal (Sxl) that removes the stop codon what sex would offspring be?

All female

What would you expect to happen if you make an SFF1 homozygous null mutant?

XY and XX embryos would not form a biopotential gonad

ß-catenin is necessary for ovary development. Which factors are necessary for its activation?

Rspo1 and Wnt4

A 17 yr old male patient has shown up in clinic with a lack of secondary sex characteristics, a very high BMI (obese). His testosterone levels are low. You suspect which endocrine disorder

Frolich syndrome

You have diagnosed your patient as potentially suffering from Frohlich syndrome. What would you look for to confirm this?

Hyphothalamic tumor

A male patient demonstrates a complete lack of spermatozoa in his semen. This is what?

Azoospermia

You are seeing a healthy appearing 31 yr old patient to diagnose her infertility. On ultrasound you can see no evidence of any follicles in either of her ovaries. What would you diagnose?

Premature ovary failure

A woman has lost both fallopian tubes due to ectopic pregnancies. Which would be the most likely method of IVF used in this case?

In vitro fertilization and implantation of blastocysts

In congenital omphalocele, a portion of the gut tube which normally develops outside the main abdominal cavity in the umbilical cord remains stuck outside at birth. Which section of the gut tube is this?

Intestines

What are the products of meiosis in female mammals?

one haploid oocyte and 2-3 polar bodies.

The brain is derived from which type of embryonic cells?

ectoderm

What are the primary sources of sex steroid hormones in both sexes?

Sertoli

An 18 year old patient that appears female comes into clinic with a lack of menstruation. Tests show the patient is missing a uterus expresses high levels of testosterone and has undescended testes. What is the most likely defect?

Androgen insensitivity syndrome

A mutation in which of the following genes is most likely to be linked to Hirschsprung's disease?

GDNF

If you have a defect that blocks release of gonadotropin releasing hormone (GnRH) from the pituitary, which sex would be affected?

Sex doesn't matter; both folliculogenesis and spermatogenesis would be disrupted.

You have a 17-year-old female patient with a lack of breast development and a lack of menstruation. She has a repaired cleft lip and palate, and neurosensory hearing loss. Serum estrogen, FSH and LH levels are low. Which of the following is the most likely cause of her hypogonadism?

Kallman syndrome

A couple in their mid 30's come to an infertility clinic after unsuccessfully trying to conceive a child. Semen analysis revealed a reasonable sperm number but a lack of motile sperm. The female partner responded to ovarian hyperstimulation, and five mature eggs were recovered. The most appropriate ART procedure to use for fertilizing those eggs in the laboratory is?

Intracytoplasmic Sperm Injection

You have a 38 year old woman with a history of early recurrent miscarriages. A sonogram of the uterus and Fallopian tubes demonstrates no abnormalities. Which of the following is the most likely cause of her pregnancy losses?

luteal phase defect

______ are the myelin producing cell in the peripheral nervous system, while _________ produce myelin in the central nervous system.

Schwann cells, oligodendrocytes

A lack of Schwann cells and the absence of major nerve clusters, such as the sympathetic ganglia, could have resulted from defects in which of the following cell types?

neural crest

Deletion of which of the following molecules is most likely to reduce the number of synapses that form in the brain?

neuroligin (normally increases # of synapses)

If you treat zebrafish embryos with an siRNA against Sdf1 what will happen to primordial germ cell migration

the PGC will migrate randomly

Pancreas forms:

gut tube derived structures result from the fusion of two separate buds off the tube

Liver forms from:

a single branch off the gut tube with the gall bladder

the stomach forms from:

the gut tube itself

gallbladder forms from:

a single branch off the gut tube with the liver

What cells in the CNS form crucial components of the blood-brain barrier that protect the brain from chemicals in the bloodstream?

astrocytes

Retrograde viral tracers are typically taken up by axons/synapses and retrogradely transported to the cell body. In the course of an experiment you are conducting, you have employed a common retrograde viral tracer based on an engineered Pseudorabies virus (PRV). You have injected a PRV vector expressing red-fluorescent protein into the spinal cord of an adult rat.

In what layer of the cortex would you expect to find labeled neuronal cell bodies?

layer 5

Your roommate is very upset with his/her ability to write with their non-dominant, left hand. Considering your knowledge of CNS development, which approach is most likely to enhance this capability?

a. Put the right hand in a mitten
b. Inject BDNF into the cortex
c. Reopen the critical period via delivery of a viral vector expressing chondroitinase ABC (ChABC)

You are studying a novel mouse mutant that exhibits some features of autism (repetitive behavior, poor sociability, high anxiety) and a large decrease in the number of neurons in the upper cortical layer (Layer 2). Which of the following genetic modifications would be most consistent with this neurodevelopmental defect?

Loss-of-function CSV in Cux1, a transcription factor important for establishing neuronal fate at the end of the neurogenic period.

A 17 year old male patient has shown up in clinic with a lack of secondary sex characteristics, a very high BMI (obese). His testosterone levels are low. You suspect which of the following disorders?

Frolich syndrome

You have diagnosed your patient as potentially suffering from Frohlich syndrome. What would you look for to confirm this?

Hyphothalamic tumor

A male patient demonstrates a complete lack of spermatozoa in his semen. This is which of the following?

Azoospermia

You are seeing a healthy appearing 31 year old patient to diagnose her infertility. On ultrasound you can see no evidence of any follicles in either of her ovaries. What would you diagnose?

Premature ovary failure

A woman has lost both Fallopian tubes due to ectopic pregnancies. Which of the following would be the most likely method of IVF used in this case?

In vitro fertilization and implantation of blastocysts

Since DES binds to the estrogen receptor and alters the normal estrogen response how would you class this endocrine disruptor?

Mimic -acts like a natural hormone, but does not need to bind the receptor

Pregnant rats were exposed to vinclozolin. The pubertal testis from vinclozolin exposed animals had significantly higher numbers of apoptotic germ cells and Sertoli cells. Based on these data which of the following is the mechanism of action of vinclozolin?

Androgen inhibitor

What accounts for the mechanism by which Planaria are able to be sliced into multiple pieces and then regenerate new animals?

stem cells within each piece producing new animals

During epimorphic regeneration in newts, what is the structure formed by dedifferentiating tissues?

blastema

syncytia are formed from

the fusion of multiple cells

Dedifferentiation of adult differentiated tissue to form a blastema is observed in .... but not......

observed in salamanders but not lizards and other amniotes

Compensatory regeneration from differentiated cells is observed in the .......but not the ......

observed in the heart of amniote vertebrates but not the tail

During tail regeneration of the green anole lizard, an amniote vertebrate like humans, which of the following is involved in tissue regrowth?

Vasculogenesis at the tip and myogenesis at the base of the regenerating tail

in morphollactic regeneration in hydra?

cells reposition and form structures without cell division

An 18 year old patient that appears female comes into clinic with a lack of menstruation. Tests show the patient is missing a uterus, expresses high levels of testosterone and has undescended testes. Which of the following is the most likely defect?

Androgen insensitivity syndrome

Your 18-year-old male friend has recently become very muscular and you believe that he may be abusing anabolic steroids. Men who abuse these hormones are at an increased risk of which of the following adverse effects?

Azoospermia

A mutation in which of the following genes is most likely to be linked to Hirschsprung's disease?

GDNF

If you have a defect that blocks release of gonadotropin releasing hormone (GnRH) from the pituitary, which sex would be affected?

Sex doesn't matter; both folliculogenesis and spermatogenesis would be disrupted.

You have a 17-year-old female patient with a lack of breast development and a lack of menstruation. She has a repaired cleft lip and palate, and neurosensory hearing loss. Serum estrogen, FSH and LH levels are low. Which of the following is the most likely cause of her hypogonadism?

Kallman syndrome

What does Bindin do?

Allows for sea urchin sperm to recognize eggs in a species-specific manner

Specification Step

Reversible step of the commitment of a cell towards a particular cell fate.

Differentiation

Irreversible step of the commitment of a cell towards a particular cell fate.

Steps of cortical granule exocytosis

-granules release Ca2+, peroxide, serine proteases and mucopolysaccharides
-causes influx of H2O and formation of the fertilization envelope

You have successfully generated ES cells for your knockout experiment that have survived double selection with neomycin and Gancyclover. What is the next step in this process?

Inject ES cells into a blastocyst

You grow mesenchymal cells in Dish A and epidermal cells in Dish . If you take the liquid medium only (containing no cells) from Dish A and place some of it into the liquid medium covering the epidermal cells in Dish B, you notice that it causes the epidermal cells to round up and thicken. What developmental concept does this example best describe?

Induction of epithelial cells by paracrine signaling from mesenchymal cells.

What is the most accurate statement about enhancers?

Transcription factors bind to enhancers

What are the products of meiosis in female mammals?

one haploid oocyte and 2-3 polar bodies.

In order to generate a mutant rodent strain with a heritable genetic modification it is particularly important that the ____________ cell lineage possess the desired mutation.

Germ

mRNA is synthesized from genomic DNA during _________ and protein is generated from mRNA during ______________.

Transcription

Translation

Instructive Inducer

Instruction from inducer to perform action

Permissive Inducer

Already specified in instructions, but needs cue from inducer to proceed.

Reciprocal Inducer

When both communicating cells can be inducer or responder

Responder

Cell that may be competent at one point in time, but can lose competency..

Describe the concept of differential gene expression.

Genomic DNA is the same in all cell types, but the mRNAs and proteins are different.

What happens when there is a loss of all sertoli cells.

Loss of all spermatogenic cells.

You have made a transgene expressing the GFP reporter gene. Where will this transgene integrate into the genome?

A random chromosomal location

What is the correct 5' to 3' order of genomic elements of a typical protein coding gene?

promoter, UTR, start codon, PolyA signal sequence.

You have discovered a new gene that you call Soprano (Sop). Sop is similar in sequence to the gene for Sonic hedgehog (Shh). What would be the best way to determine if this gene is expressed in the same places as Shh during development?

In situ hybridization using a Sop probe.

Why is a transgenic mouse not a chimera?

Injection of the transgene vector into a fertilized egg results in all embryonic cells having the transgene.

The engineered CRISPR/Cas9 system for use in gene editing has sparked a scientific revolution due to its ability to rapidly edit specific sequences in the genome. The genetic specificity of the approach relies upon what?

A synthetic guide RNA that directs binding of the Cas9 nuclease to specific sites in the genome.

What is the end product of spermatogenesis?

Haploid round spermatid

What is the genomic signal that tells the cell to start transcription?

Promoter

You want to knock out the gene Herculin in chickens, but there are no chicken ES cells. What is an alternative method to inhibit Herculin expression?

Design an siRNA specific to the Herculin mRNA.

When do mammalian oocytes complete meiosis?

After fertilization.

During limb formation in human embryos, sonic hedgehog forms a gradient that regulates the _________ to __________ axis.

Rostral

Caudal

What pathway triggers the release of intracellular Ca2+ in mammalian eggs immediately post-fertilization?

Phospholipase C is activated and produces inositol trisphosphate causing the release of Ca2+ from the endoplasmic retriculum.

You have generated a transgenic nematode with a fluorescent reporter gene. After watching it for a few days, you see that some of the cells change shape, sending out long thing protrusions called axons. What best describes the process you have observed?

Differentiation

What is Cre expression under the control of?

Cell-specific promoter

Mesodermal cells at the site of the limb buds respond to beads soaked in FGF8 and grow out along the proximal-distal axis. If beads expressing FGF8 are placed under the epithelium of the back there is no outgrowth. This experiment demonstrates which of the following?

Competence

In the Wnt signaling pathway, Wnt is secreted from the inducing cell and binds to ___________ on the responding cell in this example of _______________ signaling.

Frizzled

Paracrine

Which of the following components of a targeting vector provides information regarding precisely where in the genome your genetic modification will be targeted?

Homology arms

What situations favor the entry of spermatogonia into meiosis?

Low levels of GDNF and high levels of SCF

What morphogenic cue governs the dorso-ventral axis of limb patterning?

Wnt7a

You find that a knock-out mouse for a heart gene has an early embryonic lethal phenotype. You would like to study the function of this gene during the later stages of cardiac development. Which of the following techniques would be useful?

Conditional gene targeting

Mice were made that lacked the gene encoding ZP2. How would you predict that this would affect fertilization?

It would block sperm binding to the oocyte.

Which property of ES cells make them useful for creating site-directed mutations?

They are pluripotent and will integrate vector DNA by homologous recombination.

Spermatozoa must undergo capacitation before they are competent to fertilize oocytes. Which of the following events are part of capacitation?

Removal of membrane cholesterol and activation of adenylate cyclase.