ALEX II

Question 1

Protein processing

Answer 1

Specific proteolytic cleavage

Specificity driven by specific protein gene expression

Question 2

Translational control

Answer 2

Translation of stable mRNA or unstable RNA, rate of translation, mRNA stable but not translated until required
e.g. mTor Kinase - controls when particular mRNA is translated
e.g. iron regulatory protein (IRP)
iron regulatory element forms secondary structure - prevents ribosome binding – no initation, when iron levle increases, IRP CANNOT bind to IRE –> translation

Question 3

Post transcriptional control

Answer 3

mRNA stability

e. g. RBCs
- mRNAs translated by ribosomes is from progenitor cell - RNA has to be stable

mRNA translatability

Question 4

mRNA stability

Answer 4

Aspergillus nidulans:
areA gene - positively acting transcriptional regulator
activates genes in absence of ammonium and turns them on
Presence of ammonium: transcript halflife =10mins, chew off As
Absence of ammonium: transcript half life = 40 mins

Question 5

Homothallic:

Answer 5

HO: strains can mate with themselves, with HO - can switch mating type

Question 6

Heterothallic

Answer 6

ho: strains msut mate with opposite mating type

HO > ho

Question 7

swi5

Answer 7

Important for mating type switching

Question 8

Overexpress SWI5

Answer 8

Mother and daughter both have HO

Question 9

Ash1

Answer 9

OPPOSITE TO SWI5
Deletion of ash1: both have HO
Overexpression: neither have HO

Question 10

Drosophila Sex determination

Answer 10

Female: 2X for every autosome - turn on splicing of sex lethal locus –> transformer locus –>female development/behaviour

Question 11

DNA methylation

Answer 11

CpG doublets
1.De novo methylase - generally methylated on both strands
opposite = demethylase
2. maintenancy methylase

Question 12

C.albicans

Answer 12

White state: EFG1 represses WOR2
Opaque state: WOR2 and WOR1 mutually expressing each other, wor1 is slef regulatory –> CZF1 –> blocks EFG1 –> no white phenotype

Question 13

Epigenetic X chromosome inactivation

Answer 13

inherited

Question 14

DNA methylation

Answer 14

De novo - doesn’t have methyl

maintenance - methylation pattern retained when cell divides

Question 15

Prions

Answer 15

Proteins

Question 16

DNA binding proteins

Answer 16

Further away in eukaryotes than bacteria, upstream/downstream or in introns

Question 17

Insulator

Answer 17

Blocks transcription

Transcription factor already bound

Question 18

Enhancers acting in Trans

Answer 18

Odorant receptors: transmembrane proteins in nasal passages that detect diff chemicals
Each cell has its own pattern of odoront receptor (1 gene - 1 odorant chemical)
H enhances activates ONE gene in cis or trans

Question 19

DNA binding measuring

Answer 19

In vitro: mobility shift assay, footprinting, oligonucleotide selection, affinity purification
In vivo: ChIP: DNA protein interactions
In silico: Computer algorithims, compare sequences to identify conserved binding sites across orthologous genes/closely related species

Question 20

ChIP:

Answer 20

in vivo
Light up spots for DNA fragments or sequence
Anything you have an antibody for
Epitope tag

Question 21

Transcription factor

Answer 21

DNA binding domain
Dimerisation domain
Nuclear localisation domain
Interaction domain - modulate activation or repression

Question 22

DNA binding motifs

Answer 22

C2H2 - Zn finger, work in multiples, interact with major groove
Helix-turn helix: 3 helicies e.g. C1 repressor
Leucine: 2 domains interact
Helix-loop helix: Interaction