Transcript AP2/EREBP Transcription Factor

AP2/EREBP
Transcription Factor Family
Garen and Joanna
Transcription Factors
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Transcription Factors (TF) are proteins that
regulate the transcription of genes
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Three general categories of TFs
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Bind to RNA Polymerase
Bind to another TF
Bind to specific DNA sequences
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Most bind upstream of the target gene in the promoter
sequence
What is AP2?
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AP2 derives name from APETALA2 protein
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Unique to Plants
Contain either 1 or 2 AP2 Domains
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Domain sequence of 70 amino acids
EREBP and AP2 subfamilies
Present during many stages of plant
development in all organs
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Our focus is seed development
3 Types of AP2 Proteins
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Three classes of single AP2 repeat proteins
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Ethylene Response Elements Binding Proteins
(EREBPs)
Dehydration Response Elements (DREs)
RAV1 and RAV2
Sub-families of AP2
Sub-family
Binding
Sequence
EREBP
RAV
DRE
TAAGAGCCG
CC
CAACA+
CACCTG
[ag]CCGAC
What is its role in plants?
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Are involved in various aspects of plant
growth and development
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Flower Development
Hormone signal transduction
Cellular Differentiation
Responds to biotic and abiotic stresses
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Drought (DREs)
Low Temperature
Pathogens
More specifically…
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Certain AP2 genes control seed mass and
seed size in Arabidopsis.
May negatively affect gibberellin activity in
regulating cell size and number during seed
development
Large seed size correlates with deformed
flowers
Mechanisms
Wildtype Seed
Seed size affected two different
ways when AP2-10 is nonfunctional
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Wildtype Seed Coat
1)
Seed cavity size enlarged
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This allows for extended growth of
cotyledons
Mutant Seed
2)
Prolonged mitotic activity after
torpedo stage leads results in
extended growth of embryo
Mutant Seed Coat
Conclusion
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AP2 transcription factors are crucial to many
plant processes
Its effects on seed development may have
significant repercussions in other organs, as
exemplified by deformed flowers
Masking?
There’s still much we don’t know, but the
research continues