Name Student ID Zoo 470 Exam 1 Spring 2014 February 26 2014 Key This exam has a total of 6 pages and a total of 50 points You will have 90 minutes to complete it Please put your name and student ID on all pages Good luck 1 Provide brief definitions for each of the following 4 points a Yamanaka factor Transcription factors when expressed in combination that cause differenatiated cells to revert to a pluripotent state Not needed typically four proteins Oct4 Sox2 Klf4 c Myc although not all are needed to convert all cell types b Sertoli cell A cell type in the seminiferous tubules of the testis Sertoli cells are connected to developing spermatids and provide nutrients and metabolites to the spermatids via cytoplasmic bridges c Cortical granule Organelle immediately beneath the plasma membrane of an unfertilized egg Cortical granules are released upon fertilization resulting in the permanent block to polyspermy and remodeling extracellular protein surrounding the egg d Localized determinant A substance that is inherited by specific cells in an embryo that once inherited confers on them the ability to differentiate in a particular way An example is myoplasm in the ascidian embryo 2 Reproduction in humans is regulated by hormones A major pharmaceutical company has used this fact to develop commercial products a One product on the market is targeted towards women having difficulty becoming pregnant It detects two pituitary hormones in urine that correlate with the ovulatory cycle What hormones should this kit test for 1 point Two hormones used in the kit FSH LH c A third product produced by this company is a home pregnancy test that tests for successful conception i e fertilization within 7 days of the event What hormone does this product test for 1 point Hormone used in the kit HCG 0 5 pt for progesterone d RU486 interferes with the normal function of progesterone during early pregnancy Name one important target of progesterone that is affected by the drug 1 point Tissue uterus endometrium ant pituitary or hypothalamus e What tissue s or cells normally produce progesterone 1 point Tissue corpus luteum 0 5 pt for ovary Page 1 Name Student ID 3 Circle true T or false F for each of the following 8 points F Targeted gene insertion by homologous recombination is a technique that is specific to mouse ES cells and not generally applicable to other mammals such as humans done in human ES cells F Like European Union countries the United States has passed legislation outlawing human cloning no federal laws just restrictions on funding F Smoothened receptors are important in embryos because they allow attachment of migrating cells to the extracellular matrix involved in Hedgehog signaling T F T F Unlike mammalian sperm sea urchin sperm produce a long acrosomal process Experiments involving separation of sea urchin blastomeres indicate that the right and left halves of early sea urchin embryos are autonomously specified in the 2 or 4 cell embryo conditionally specified totipotent The formation of the fertilization envelope in sea urchins involves release of proteoglycans from cortical granules which swell to help lift off the vitelline envelope Wnt signaling always leads to accumulation of catenin in the nucleus of the responding cell leading to changes in its state of differentiation not in PCP signaling F If a female zebrafish is homozygous for a maternal effect mutation that is lethal and she is mated with a wild type male one quarter of her offspring will die all die F One outcome of cloning by nuclear transplantation in endangered species is an increase in genetic diversity due to a decrease in the size of the gene pool decrease Once mammalian sperm are produced following meiosis their final maturation occurs in the seminiferous tubule epididymis In mammalian cloning experiments Dolly was a surprise because cloning from embryonic cells had previously been shown to be impossible in mammals had been done from embryos In the organizer experiment of Spemann the resulting secondary axis is formed entirely from the implanted material some induced from host Sorting out experiments indicate that different differentiated cells have different cell surface properties Fertilization of a mammalian zygote typically occurs in the oviduct note the oviduct is called the Fallopian tube in humans A clone produced by transplanting a nucleus from a somatic cells of a wildtype mouse into an enucleated oocyte from a female mouse carrying a disease causing mutation in the mitochondrial genome would likely be free of mitochondrial related disease oocyte has the defective mitos so clone would have defect ES cells can generate many differentiated cells types but not cells that give rise to sperm or oocytes they can even result in viable mice F F F T T F F 4 Isolation of cells with extensive developmental plasticity is a major goal of regenerative medicine a Provide two pieces of evidence that pre compacted mammalian embryos are totipotent 2 points Evidence 1 Allophenic mice combing three embryos to form a single giant yet normally differentiating blastocyst Evidence 2 Embryo splitting blastomere isolation separated blastomeres will develop into complete embryos Page 2 Name Student ID 4 cont b Are inner cell mass cells from which embryonic stem ES cells are produced totipotent Explain your answer Are ICM cells totipotent Circle one 1 point Yes No Explanation 2 points No they are pluripotent under normal circumstances because they cannot form extraembryonic tissues c You are in Shinya Yamanaka s lab in Japan and you are competing with Jamie Thomson s group to find new ways to perform induced pluripotency You have induced human cells that you believe are pluripotent Describe one experiment that would show that your induced human cells seem to be pluripotent 2 points Use nude mice implant ES cells into mice and look for teratomas Although unethical we would accept making chimeric human embryos Some credit for culturing and showing that they can make many things by treatment with growth factors d At least some induced pluripotent iPS cells in mice are now known to be truly pluripotent Provide one piece of evidence showing that this is true 1 point Two options 1 Place iPS into host blastocyst these will incorporate noprmally chimeric mouse 2 Tetraploid complementation if the ICM is derived from only iPS cells it can make a baby mouse 5 Cloning by somatic cell nuclear transfer in mammals has raised several scientific and