This web page was produced as an assignment for Genetics 677, an undergraduate course at UW-Madison.
RNAi
RNA interference(RNAi) is a useful technique in genetics to help determine the function of a gene. The basic technique is to stop a gene's functioning in an organism by inserting micro-RNAs (miRNA) and small-interfering RNA(siRNA) into the organism. RNAs are direct products that are coded from an organism's DNA. RNAi works by the small RNAs (siRNA and miRNA) binding to other RNAs in the cell, thus inhibiting it's activity. By interfering a gene and observing the effect, scientists can figure out more about what the function of that particular gene is.
There is a homolog of KRAS found in the model organism C.elegens that might help understand more about the function of KRAS in mamallisan systems. RNAi experiments have been done on the gene (called let-60). Similar to KRAS in humans, let-60 encodes a member of the GTP-binding RAS protooncogene family. It is required for viability, vulval development, germ line meiotic progression as well a host of other functions, as would be expected of a gene involved upstream in many pathways.
let-60 encodes a member of the GTP-binding RAS protooncogene family; let-60 activity is required for viability, vulval development, spicule development, germ line meiotic progression, posterior development of the hypodermis, chemotaxis, sex myoblast migration, and muscle membrane extension; let-60 acts genetically downstream of let-23 with respect to vulval development and upstream of the MAPK pathway with respect to chemotaxis; let-60 is expressed in neural, muscle, and hypodermal lineages
There is a homolog of KRAS found in the model organism C.elegens that might help understand more about the function of KRAS in mamallisan systems. RNAi experiments have been done on the gene (called let-60). Similar to KRAS in humans, let-60 encodes a member of the GTP-binding RAS protooncogene family. It is required for viability, vulval development, germ line meiotic progression as well a host of other functions, as would be expected of a gene involved upstream in many pathways.
let-60 encodes a member of the GTP-binding RAS protooncogene family; let-60 activity is required for viability, vulval development, spicule development, germ line meiotic progression, posterior development of the hypodermis, chemotaxis, sex myoblast migration, and muscle membrane extension; let-60 acts genetically downstream of let-23 with respect to vulval development and upstream of the MAPK pathway with respect to chemotaxis; let-60 is expressed in neural, muscle, and hypodermal lineages
Expression of let-60 in C.elegens
let-60 expression in C.elegens.
RNAi phenotypes
Many RNAi experiments were done before to figure out the function of let-60. Below are the observed phenotypes:
- sterility
- lethality
- larval arrest
- locomotion variant
- larval lethal
- sterile progeny
- reduced brood size
- embryonic lethal
- slow growth
- sick
- protruding vulva
- organism morphology variant
- organism developmental variant
- cell secretion variant
Analysis
From the variety of phenotypes observed from RNAi experiments on C.elegens against let-60, we can conclude that the gene plays an important role in many functions particularly related to growth. From this, we can deduce that let-60 likely lies upstream on many biological pathways in C.elegens. Thus, disrupting it's function in C.elegens causes defects in many different areas relating to growth.
References
Worm Base Gene Summary for let-60
http://www.wormbase.org/db/gene/gene?name=WBGene00002335
http://www.wormbase.org/db/gene/gene?name=WBGene00002335
