Mike genes in action extra facts

Question 1

Epigenetics how relevant?

Answer 1

Want to take cells and make undifferentiated for regenerative medicine
Want to stop methylation shutting off regions of DNA

Question 2

What is piwi-RNA?

Answer 2

Small RNA found to be expressed in germline, job is to stop transposable elements jumping around genome
(they can jump out of genome , make RNA trancripts, use reverse trancriptase and jump back in)
Jumping genes can be dangerous if they land in the middle of a gene –> CANCER

Question 3

What does piwi RNA do?

Answer 3

Binds complementary to jumping RNA and stops it jumping back
Important because any mutation in germ line passed on to all progeny so they protect what gets passed on to progeny
Scientists were confused about piwi-RNA for ages

Question 4

How are TFs important?

Answer 4

Talk about oct4 thing, makes all DNA repoen eg. they regulate histone modifications which changes DNA packaging

Question 5

What cool bacteria have they made?

Answer 5

Bacteria using 4 nucleotides instead of 3

Unnatural amino acid tRNA –> forms long rigid proteins which in humans could theoretically make v strong skin

Question 6

As eukaryotic cells divide what happens to numbers of origins activated?

Answer 6

Reduces as more regulation, what controls no. origins turned on is a big research topic

Question 7

In cancer cells what happens to origins?

Answer 7

Lots of origins activated allowing cancer cell to divide much more quickly
Cancer cells like mutations because allows them to avoid drug etc.

Question 8

What happens in eukaryotic cells if origins fire more than once during replication?

Answer 8

Anaploidy, simplest case is messed up chromosomes and cell death

Question 9

What is the end problem and how many bases are lost each replication round?

Answer 9

See essay for diagram- 50-200 bases lost every eukaryotic replication round
Solution is telomere
If telomere length too short get double strand break–> p53 activated and pushes cell into senescence (not needed in prokaryotes)

Question 10

What happens with telomerase in the early embryo, how do cancer cells exploit?

Answer 10

Makes cells immortal (cells divide a lot to make up mass)

Cancer cells become immortal cells by taking advantage of telomerase found a lot in stem and germ line cells