Fertilisation IV

Question 1

What does the sperm cell have little of?

Answer 1

Cytoplasm

Question 2

What happens to PLCzeta null male mice?

Answer 2

They are still fertile

Question 3

How can intracellular Ca2+ release be measured?

Answer 3

using Ca2+-sensitive fluorophors

Question 4

What happens to mouse protamines after 30 mins?

Answer 4

Removed

Question 5

What removes the mouse protamines?

Answer 5

acidic, oocyte proteins: nucleoplasmins

Question 6

What happens to the sperm during protamine replacement?

Answer 6

They decondense–> chromatin occupies a larger volume

Question 7

When are the sperm protamines replaced?

Answer 7

During mII exit when the sperm enters the egg

Question 8

What replace the protamines?

Answer 8

Maternally derived histones

Question 9

What forms the prunucleus?

Answer 9

Recondensed sperm chromatin and maternal chromatin

Question 10

What happens to the hustones of maternal and paternal chromatin?

Answer 10

DYnamic modification–> epigenetics

Question 11

What happens to the maternal and paternal genomic DNA?

Answer 11

It is demethylated

Question 12

What happens to the sperm’s volume as the protamines are removed and replaced by histones?

Answer 12

It increases

Question 13

Why are the maternal histones floating around?

Answer 13

No nuclear membrane in the fertilised egg

Question 14

What is the sperm nucleoprotein exchange independent of?

Answer 14

DNA rep

Question 15

What kind of modification do histones in both parental chromatin sets have?

Answer 15

N-terminal modification

Question 16

Why can the histone N terminal tails be modified?

Answer 16

They are solvent exposed

Question 17

What is chromatin regulation integrated with?

Answer 17

Histone modifications

Question 18

What may contribute to transcriptional asymmetry?

Answer 18

Modifications differing between parental chromatin sets

Question 19

How can the kinds of histone modifications be visualised?

Answer 19

Antibodies that recognise specific modifications on histones can be made

Question 20

What are some paternal histone modifications in one-cell embryos?

Answer 20

H3K4me3, H3K9me2, H3K27me3

Question 21

What are some maternal histone modifications in one-cell embryos?

Answer 21

high H3K4me3, H3K9me2/3, H3K27me3

Question 22

What are some histone modifications in one cell embryos that occur in both parental chromosomes?

Answer 22

high H4K12ac and other histone acetylation

Question 23

Maternal/paternal histone modifications delayed/throughout?

Answer 23

Paternal ones = delayed
Maternal ones = throughout

Question 24

How many eggs can be superovulated with one mouse?

Answer 24

20

Question 25

What is the embryonic chromatin analysis at high resolution method called?

Answer 25

CUT&RUN

Question 26

How does CUT&RUN work?

Answer 26

use an antibody against a TF, TF binds a region nuclease then chops the genome up antibody is “Pulled down” and captured DNA can be eluted and sequenced

Question 27

Difference between CUT&RUN and ChIP-seq?

Answer 27

CUT&RUN is more sensitive

Question 28

What happens to 5mC after fertilisation?

Answer 28

Oxidised to 5-hydroxymethylcytosine

Question 29

Which parental set of DNA does the oxidation of 5mC to 5-hydroxymethylcytosine mainly happen in?

Answer 29

Paternal

Question 30

What mediates the oxidation of 5mC to 5-hydroxymethylcytosine?

Answer 30

Ten-eleven translocase (Tet) enzymes

Question 31

What is 5fC?

Answer 31

5-formylcytosine

Question 32

What is 5caC?

Answer 32

5-carboxymethylcytosine

Question 33

When is Tet3 expressed?

Answer 33

Oocytes and early embryos

Question 34

Whta happens if Tet3 is knocked out?

Answer 34

~80% reduced fertility

Question 35

What is the elongator complex 5mC requires?

Answer 35

Elp1, Elp3 and Elp4