The least you need to be able to explain to yourself:
- how do you go from one cell to many cells that look different, act differently and work together in a coordinated way;
- the connection between gene expression, regulation of gene expression, differentiation and development;
- a few examples of types of proteins (gene products) that are involved in development (e.g. TF, signalling proteins, etc)
- a few examples of how the action of a gene, or that of a protein, can be regulated (transcriptional level, translational level, post-translational....)
- how you can get a cell to grow out of control (what "things gone wrong" may cause this)
- what type of mutations can affect cell cycle
- how to show that DNA element X( e.g. a module of an enhancer) is necessary and sufficient to confer a particular spatio-temporal expression pattern to your gene of interest;
9 comments:
Are Enhancer Traps and Promoter Traps just fancy gene tagging?
Pair-Rule genes.
The notes say that they are seen in a pattern of 3-4 cells with expression followed by 3-4 cells without expression. Does that describe how an individual gene opperates? Are they all doing that in a staggered pattern?
Thanks!
Traps: YES.
Pair rule genes:It describes the pattern of expression, and yes, they are all expressed like that. Each gene is expressed in 3-4 adjacent cells, and then not expressed in the next 3-4 cells, and so on.
Rb protein mutation in retina leads to tumor formation in the retina. Is this Rb protein retina specific? If not, how come the mutation in Rb protein did not induce tumor formation in other tissue types?
Gap + pair rule protein expression:
1) if low level of both bcd & hb-m is required for the expression of kr, then how come in absence of bcd, Kr is still expressed?
2) if bcd is required to induce hb-z expression and inhibits kni expression, then how come the domain of expression in hb-z & kni overlap? (diffusion?)
Q about nano mutation
in the textbook it says nanos mutation
will cause bicaudal phenotype..
why would it cause bicaudal phenotype...
and not just one elongated caudal phenotype?
like a nanos mutation?
Rb protein:
excelllent question. No, the Rb protein is not retina-specific. To these day, we still don't know why a LOF mutation in Rb first causes tumors in the retina (several hypothesis are around).
In reality, people with no Rb protein develop tumors in other parts of the body as well.
Gap and pair rule genes questions:
Kr will be expressed, but mis-expressed (i.e. not expressed in its NORMAL pattern.)
The domains of expression of the gap genes do overlap, but you'll see that where they overlap, they are both expressed at very low levels. The two genes can be expressed in the same region, but because they are inhibiting each other, they will both be expressed very very little in the overlapping region.
Nanos mutation and bicaudal phenotype:
don't worry about the bicaudal phenotype (we have not done it in class). For our purposes, a nanos mutation will result in no gradient of hb-m, which will impair the formation of a posterior (and also, it will result in a completely defective A-P axis!)
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