3. The wnt transcription pathway is responsible for key changes during animal development. Based

3. The wnt transcription pathway is responsible for key...

Key Concepts

Wnt Signaling

The Wnt signaling pathway is a fundamental mechanism in animal development that regulates cell fate, proliferation, and patterning. It typically works by stabilizing downstream transcription factors that, when activated, trigger the expression of target genes necessary for developmental processes.

Signal Transduction Pathway

Signal transduction pathways are sequences of molecular events by which cells respond to external cues. In developmental biology, they are essential for converting extracellular signals into specific gene expression responses, ensuring proper cell differentiation and tissue formation.

Gene Regulatory Network Diagrams

Gene regulatory network diagrams use visual symbols such as arrows to represent the activation or transformation of molecular species and bar-like lines to indicate inhibition. This helps in the interpretation of how changes in the expression level of one gene, like increased Wnt signaling, can positively or negatively influence the expression levels of downstream components.

Transcript

00:02 We are given a pathway and we are being asked a question about the pathway, namely, how would increased want gene expression effect bar one? now, i know initially when you are learning this stuff, all of these acronyms can get a little bit out of hand.

00:26 But in all honesty, you don't really need to know exactly what every single one of these things does in order to, follow the flow of information, right? you are given this schematic and you can read it and let's just see what we can do.

00:41 So at level one, we have this thing called want.

00:48 Want upregulates level two, which is frizzled.

00:51 Frizzled upregulates level three, which is disheveled.

00:57 Dishevelled, down regulates level four, which is the beta catenic.

01:03 I'm sorry actually i apologize level four is down here disheveled done regulates level four which is the axon and the gsk these two down regulate beta catanins level five and beta catanins and tcf upregulate the expression of this gene called the hox gene okay so i'll try to make sense of all of this practically in a second but let's just stick with this for now so we are being asked how would want gene expression affect the expression of bar one okay so how would increased expression at level one affect expression of beta catanin which is basically bar one these two are the same thing okay just different names for the same thing so let's just follow the flow and this is how you want to generally approach these kinds of questions so increased levels of up one would absolutely result increased levels of level two increased levels of level two would result in increased levels of level three okay right because that's what this arrows mean and the green arrows that i'm that i'm drawing here basically represent more or less activity of that level now since level three blocks the expression of level four that means that you would have less activity at the leg at the level four now since you have less activity at level four and level four also blocks level five less level four means more level five and more level four means less level five okay so let me say that again because level four down regulates level five if you have more things at level four you are going to have less things at level five if you have less things at level four you are going to have more things at level five sorry let me draw a better arrow ahead there you are going to have more things at level five and then more things at level six okay these can be flow diagrams for anything okay and you can follow the same logic so the answer here is that increased level of want gene expression will result in increased expression of beta catanids okay so if this question was in an exam that would be the answer now let me make this a little more concrete for you and tell you what they're actually talking about here genes are genes that govern the setup of a body plan during embryonic development.

04:09 So in embryo, when you go from a zygote from a single cell to an actual human being, that cell needs to differentiate.

04:19 And the hoax genes are a set of genes that basically help the development of the body plan.

04:27 Now if you notice here, the beta catanins, so this is the nucleus here, so this is the nucleus here, at the bottom.

04:37 The beta catanins, the beta catanins and tcf locate to the nucleus, and when they locate to the nucleus, they help transcribe those genes, those hoax genes.

04:52 However, when they interact with axon, okay? when they interact with axon, they cannot go to the nucleus and help transcription...

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