Regulation of Replication

Question 1

what is the eclipse period ?

Answer 1

The eclipse period in DNA replication refers to the phase during which newly synthesized viral genomes are not yet encapsidated and are undetectable, and occurs between the end of viral eclipse and the onset of viral assembly.

Question 2

how is initiation of chromosomal replication at oriC regulated?

Answer 2

through control of initiator protein DNA A

Question 3

what is the difference between DNAA-ATP and DNAA-ADP

Answer 3

DNAA-ATP is active and DNAA-ADP is inactive

Question 4

what is DUE?

Answer 4

DNA unwinding Element (DUE) is AT rich and easier to unwind AT rich DNA duplexes.

Question 5

where is DNA unwound

Answer 5

at the DUE

Question 6

what affinity are the binding sites in the oriC

Answer 6

both high and low

Question 7

IHF and FIS are examples of what?

Answer 7

binding sites

Question 8

what is required for complex formation

Answer 8

IHF

Question 9

what does the eclipse period equate to?

Answer 9

the control of DNAA expression, availability, activity

Question 10

where is the DNAA gene located

Answer 10

adjacent to the origin of replication

Question 11

how many promoters has DNAA ? name them? and what percent of these are transcriptors?

Answer 11

it has two promoters, P1 and P2, P1 is 30% transcripts and P2 is 70% transcripts

Question 12

when is P2 not active

Answer 12

when DNA is hemi-methylated

Question 13

what is DAM methylase

Answer 13

DAM methylase is a bacterial DNA methyltransferase enzyme that specifically adds a methyl group to the adenine residue in the GATC sequence of DNA

Question 14

what is DNAA a repressor of

Answer 14

DAM methylase

Question 15

what does the dat locus do

Answer 15

binds DNAA at a high number of monomers, lowers the cellular level of DNAA protein and this reduces its availability to engage in re-initiation of chromosomal replication

Question 16

what is the DARS loci and what is it involved in

Answer 16

DARS loci (DNA replication-related element-associated sRNA) are genetic elements in bacteria that are involved in regulating DNA replication and other cellular processes. involved in reactivation of DNAA-ADP -> DNAA-ATP

Question 17

How many GATC sites are there within the minimal origin ? how many are expected?

Answer 17

11. expected to be 1

Question 18

what are GATC sites methylated by?

Answer 18

DAM methylase

Question 19

what can taql distinguish between?

Answer 19

can distinguish between fully and hemi methylated DNA

Question 20

where is OriC located and where does termination occur

Answer 20

oriC located at 0 degrees on chromosome and termination occurs at almost 180 degrees on the chromosome

Question 21

what is the T loop ?

Answer 21

telomere loop that is formed by invasion of telomeric DNA by G rich ssDNA

Question 22

what is the D loop

Answer 22

displaced DNA loop/ displaced ssDNA region after G rich strand invasion

Question 23

how are telomeres replicated

Answer 23

with a special enzyme called telomerase

Question 24

what do somatic cells not express and what does this mean for them

Answer 24

they dont express telomerase, so they are shortened with each division until they reach a critical length.