Notes taken during lecture

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Published on 6 Apr 2011
School
UTSG
Department
Biology
Course
BIO120H1
LECTURE April4th, 2011
CELL DIFFERENTIATION
How cells make themselves different from neighbouring cells
Focuses on cell specialization and cell interaction
Intrinsic
Less common
Depends on unequal segregation of something during cell division
Original cell before division is asymmetric
One daughter cell inherits all of the determinant, the other doesnt get any
Can be transcription factor things that affect transcription that affects
transcription right after division
Extrinsic
Signal from other daughter cell changes fate, developmental capacity, forming
some cell type
Cell without signal stays the way it is
Intrinsic used commonly by c. elegans
Every line is a cell division
Divisions continue and parts of them
Part of division part is shown all the way down to the adult
From first cell division to 1100 cell
Specific lineage
Germ line forms from cells b-granules segregated to one side of embryo
oCell division polarized across horizontally
oGerm line determinant
oAbp, ms, ems- do not need to know
oAsymmetric cell division partitions cell fate determinants to determine
oRequires cortical polarity and proper spindle alignment
Extrinsic mechanisms
First one is lateral inhibition
oLateral on the sides
oCreates a pattern of isolated differentiated cells
oBy notch signalling
Delta is transmembrane signal
Like boss
Interacting with notch, transmembrane protein
2 cells, both expressing signal and receptor
Activation of receptor inhibits specialization in both cells
Then by chance, a cell expresses a little more delta, more notch
activation in lower cell, then turns off own delta of lower cell
Receiving cell no longer expresses delta
Bottom cell is sending cell
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