BIOL-100B Advanced Cell Biology Research Article Assignment1 Due: On LATTE, 11:59pm January 21st, 2018. Not accepted late. AssociatedReading: Golgi maturation visualized in living yeast.
Losev E, Reinke CA,Jellen J, Strongin DE, Bevis BJ, Glick BS. Nature. 2006 Jun22;441(7096):1002-6. Epub 2006 May 14. Paper and supplements are available moreconveniently on LATTE. Note: Questions 1-6 are worth 1 point and will be gradedindividually on “good faith effort.” This means that you do not need to havethe correct answer to get full credit, but you do need to demonstrate that youcarefully read the paper and tried to answer the question correctly. Any ofthese questions could appear on any of the tests.
If they do, they will be gradedfor correctness. Question 7 is optional and will not be graded. How to submit:This assignment must be submitted online via Latte, as a pdf or text document. 1. What is the bigquestion of this paper? Not, what is this paper about, but what problem is thisentire field trying to solve? What is the nature of the early (cis, medial) and late(trans, TGN) cisternae and how do they mature?2.
Summarize thebackground in five sentences or less. Bullet points are ok. · Determine florescence of early Golgi proteinstagged with GFP and late Golgi protein with DsRed using S. cerevisiae· The Golgi Dynamics were examined using 4Dmicroscopy, using markers Sec7 for late cisternae and VRG4 for early cisternae.· The Maturation Mechanism was consistent throughcarboxypeptidase and visualized cisternal maturation by tagging both markers atthe same time – GFP withVrg4 and Sec7 with DsRed. · Futureexperiments will test the association between maturing cisternae and secretorycargo proteins 3. What is(are) thespecific question(s) of this article (i.
e. what exactly are the authors tryingto answer with their research)? · Does the rate of cisternal maturation match therate of protein transport? o Was the composition of Golgi-resident proteinschanged over time when visualized individually?o How are they going to use light microscopy sothat they can distinguish individual cisternae?o How were they going to fluorescently tag Golgimarker proteins that were highly expressed while not affecting the organelle?4. What experimentalsystem and approach are they using? 3D time-lapse fluorescence microscopy of yeast S. cerevisiae5. Explain Figure 4and S6: a. Describe the experiment. Radioactive pulse-chasemeasurement with rapidly secreted protein in yeast, Alpha-factor was used todetermine whether the experiments done were accurate and the maturation matchedthe rate of secretory traffic.
In the Alpha- factor, the core slowly disappearedat time went on, and in the Carboxypeptidase Y, the gel shows that as time wenton, the mature bands showed darker and darker bands. b. What question(s) do(es) this experimenthelp the experimenter answer? Is there a speeddifference between Golgi-to-cell surface transport and intra-Golgi transport? c. What results are shown in this figure?Be sure to explain the axes, what is being depicted in the associated panels inthe supplemental figure, and the meaning of any variables. A.
TheBand intensity (% of max) is the y axes and it is describing the band on figureS6 and how the core at .5 min was at 100% and then decreased to 0% by minute10. And the maturity in figure S6 increased to 100% intensity by minute 14(x-axes is chase time in minutes). B. ForCarboxypeptidase Y, even though is it less accurate, showed a similar graphwhere band intensity of p1 is 100% from 0-2min, and maturity reached around 80%by minute 40. For both graphsthe red line indicated ER-localized core and p1, and the blue dotted lineindicated halftime disappearance and vacuole-localized mature CPY.d. How do the results contribute toanswering the question(s) you outlined in “B”? These results indicatethat Golgi-to-cell-surface transport is in fact several times faster than intraGolgi transport which goes back to the original question of the paper which wasthe rate of cisternal maturation.
6. Do the results ofthis paper help the answer the big question you outlined in “1?” Why or whynot? Yes, but to a degree, it answers part of the big question ofthe rate of cisternal maturation, which is a portion of the bigger question,but more research needs to be done to actually answer the full question. Butthis study will help forward the future research. 7. Is there anythingyou’d like the presenter(s) to know or address during their presentation? Forexample, questions about terminology, methods, or results. Great videos,diagrams, or other resources you may have found.
(optional)I thought P1 and p2 were poorly explained, andthink it would be interesting to maybe address more what they are and thenreanalyze