Developmental Transcription Factors

Question 1

Signals and transcription factors that regulate somite patterning

Answer 1

Shh, Wnt, BMP, and Fgf are signalling molecules that regulate development in concert with transcription factors (Pax3/7, Myf5, MyoD - all critical for muscle specification and development)

Question 2

Transcription control of cell fate

Answer 2

MyoD confers muscle cell identity by regulating other genes, Transgenic expression of MyoD drives conversion to muscle lineage

Question 3

Chemical affinity

Answer 3

Receptors on the surface of cell has ligands that recognize different thing, chemical affinity is the first interaction between us and the world

Question 4

How do cells know what genes to turn on or off

Answer 4

Transcription factors like MyoD bind specific regions of the genome, MyoD is apart of the family of TFs called basic helix loop-helix proteins, and binds E-box sequence as a heterodimer with E-proteins

Question 5

Active MyoD

Answer 5

When MyoD is active, certain transcription factors are always present, such as SIX1/4, MYF5, PAX7

Question 6

Enhancers

Answer 6

Regulatory transcription factors bind to specific sequences of nucleotides near their target genes, work as activators or repressors, specifc DNA sequences are recognized by specific proteins, which can then change the way DNA is packaged

Question 7

Enhancers are normally

Answer 7

Bound by multiple transcription factors, ensures enhancers are active in the right place at the right time

Question 8

Promoter

Answer 8

start sites of genes, promoter recognition by general transcription factors

Question 9

TFIID

Answer 9

recognizes the promoter and recruits RNA pol II

Question 10

TFIIH

Answer 10

catalyzes RNA pol II phosphorylation to initiate transcription

Question 11

Steps of start sites of a gene

Answer 11

1) TFIID binds to TATA box in DNA
2) TFIIA and TFIIB form complex with TFIID
3) Resulting complex is bound by RNA polymerase attached to TFIIF
4) Preinitiation complex is completed by addition of TFIIE an dTFIIH
5) RNA polymerase CTD undergoes phosphorylation

Question 12

DNA repair

Answer 12

not equally distributed, treats different parts of genome differently, genes that are currently being expressed are the ones that are repaired 100% of the time, the genes that are not currently being expressed are not always repaired right away

Question 13

E boxes

Answer 13

MyoD binding sites

Question 14

MEF3

Answer 14

Six4 Binding site

Question 15

MEF2

Answer 15

MEF2 binding site (myocyte enhancer factor) Necessary for muscle and other cells, only activates genes when cells receive proper signals, muscle-specific genes require activation of MEF2 and MyoD expression

Question 16

Nucleotides -133 to +18

Answer 16

Confer expression in embryonic day 13.5 trunk muscle and limbs

Question 17

Cooperations by transcription factors

Answer 17

MyoD converts fibroblasts to myosin heavy chain positive myotubes

Question 18

Transcription factors and co-activators

Answer 18

Transcription factors bind DNA and the recruit co-activators that regulate gene expression, Like CREB, MEF2 must be phosphorylated before it can bind co-activators

Question 19

MyoD, MEF2, and Six4

Answer 19

recruit different co-activators to activate target genes (all members of the team are members)

Question 20

Co-activators and co-repressors

Answer 20

regulate epigenetic marks to control gene activity

Question 21

Histone acetylation

Answer 21

leads to looser packing and euchromatin

Question 22

Histone Methylation

Answer 22

leads to tighter packing and heterochromatin

Question 23

Plasticity

Answer 23

memory of transitional changes somatic variability and development response to environmental cues