Question

dents in the lab applied 2640 different drugs to zebrafish embryos (that were expressing a liver ere larger or smaller than normal. They determined that multiple drugs involved in estrogen signaling were 2. The Goessling lab at Harvard studies estrogen regulation of liver development, using P) as their livers were developing, and then they used microscopy to examine whether the embryonic QUESTION 2. Th model protein fused to strong regulators of liver formation. and then travels to the liver, and it is able to signal through multiple cell pathways. a Estrogen, which is an example of a steroid hormone, can be produced in the brain ) What mode of cell-cell commun cytoplasm. Why are these receptors called "nuclear receptors"? Specifically, what is their function? (3 pts) hy an use? (2 pts) bj Upon reaching the liver tissue, estrogen can bind to receptors in the a) b) Anastrozole ("Ana") is a drug that prevents estrogen formation. E2 is an abbreviation for estrogen. DMSO is a control solution in which E2 and/or Ana are dissolved. c) Based on this graph of liver area measured at 3 days of embryonic development, what affect does estrogen have on liver development? (Circle) (3 pts) 15 It promotes liver It inhibits liver Effect is unclear DMSO E2 Ana There are 2 different nuclear receptors that estrogen might bind to -ESR1 and ESR2. Zebrafish embryos were cultured in various conditions (with and without exogenous estrogen, and with and without drugs that block each receptor) through 3 days of development. Based on these images of the resulting livers (black blob is liver staining), d) which receptor(s) mediates the effect of estrogen on liver development? (X pts) (MPP is an ESRI inhibitor, and PHTPP is an ESR2 inhibitor) (Circle one OR both) (4 pts) РНТРР ESRI ESR2 The lab also discovered that estrogen promotes liver development after the third day of development, but for this estrogen works through a GPCR called GPER1. If a drug was added to zebrafish embryos that led to constitutivse ation of adenylylcyclase, and then extra estrogen was added after the third day of development, e) what would the liver size be on the sixth day of development? (Control condition does not have the drug NOR estrogen added.) (4 pts) Larger than control Smaller than control Same size as control f) In this same experiment, if you compared embryos incuba that ONLY were incubated in drug (condition D), what would you observe when you examine liver size? (4 pts) ted in drug AND estrogen (condition DE), versus embryos Condition DE is smaller than condition D They are the same Condition DE is bigger than condition D g) In a different experiment,if estrogen is added but cyclic AMP phosphodiesterase function is completely blocked by a teren enun what would you observe when you examine liver size, compared to a control condition with estrogen but no drug? (4 pts) Larger than control Smaller than control Same size as control In this same experiment, if cyclic AMP phosphodiesterase function is completely blocked by a drug but estrogen binding to GPER1 is also blocked (beginning on the third day), what would you observe when you examine liver size, compared to a control condition Smaller than control Same size as control with no drugs? (4 pts) Larger than control

Answer 1

2) a) endocrine signaling

b) These are nuclear receptors because they are located in the nucleus. They act as transcription factors

c) Estrogen inhibits liver

d) ESR2

e) Larger than control

f) Condition DE is bigger than condition D

g) larger than control

h) same size as control