2010 Bio 311 Lab D Manual (part 3)

2010 Bio 311 Lab D Manual (part 3) - D3. RNAi Analysis Lab...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
113 D3. Lab Overview: Last week, you performed RNA interference (RNAi) in C. elegans using an RNAi “feeding” technique. During the week, the worms and their offspring have been consuming the E. coli and taking up dsRNA. This week, you will observe the phenotype that results from RNAi of unc-22 and lsy- 2 and further analyze the results using a C. elegans chemotaxis assay. You will run the results from the PCR analysis on a gel. You will also search the BioInformatics data bases to explain your results. The nervous system of C. elegans appears morphologically symmetrical under the microscope. Both sides of the nervous system develop from a common ground state. Cell positions, dendritic axons, and synaptic connections exhibit bilaterial symmetry as seen in the figures from Johnston & Hobert (2005). However, neurons with morphological symmetry in the nervous system diverge functionally. They contain distinct receptors which recognize different sensory factors that attract or repel the worms. For example, the right side of the nervous system (ASER) contains gustatory neurons (see highlighted regions in Fig. 1B with a blue circle) involved in sensing chloride while the left side of the nervous system (ASEL) contains gustatory neurons (see highlighted regions in Fig. 1B with a red circle) involved in sensing sodium. ± Read "the Lab Overview” of Lab D3. ± State lab Goal(s) . ± Outline or make a flow chart of the methods. Fig. 1 - Adopted from Johnston & Hobert (2005) Dev.132: 5451-62 A B Sodium Chloride
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
114 The fates of these neurons are determined during worm development through gene regulatory pathways specific to each side of the nervous system. The circuitries are demonstrated in Fig. 1 A for ASEL and ASER. Genes in the circuits that appear dark are active on that side of the neuron. Not shown are transcription factors that regulate the expression of some of the neuron specific factors. lsy-2 codes for a transcription factor necessary for the development of ASEL by regulating expression of the lsy-6 gene. Interestingly, the developmental fate of the left side of nervous system in C. elegans is regulated by a cell type-specific microRNA named lsy -6. MicroRNAs are short (about 22 nucleotides), noncoding RNAs that appear to negatively regulate gene expression. For example, expression of cog-1 is needed for full functional development of the right side of the nervous system, which is the default development (see Fig. 1 A, ASER). The microRNA lsy-6 negatively regulates the expression of cog-1 in the left hemisphere of the neuron system in C. elegans allowing for left side development (see Fig. 1A, ASEL). About 2% of the genes in the human genome code for microRNAs most of which have yet to be characterized. They are the naturally occurring “RNAi” in the cell and can work with DICER and RISC to target a specific mRNA for degradation (see below).
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 03/28/2011 for the course BIO 311 taught by Professor Staff during the Fall '08 term at SUNY Stony Brook.

Page1 / 9

2010 Bio 311 Lab D Manual (part 3) - D3. RNAi Analysis Lab...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online