plant promoters

7/30/2019 Plant Promoters

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Plant Promoters


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Promoters:

A site in a DNA molecule at which RNA polymerase and

transcription factors bind to initiate transcription of specific

genes to mRNA

The promoter acts as the regulator for the level of gene

expression.

Promoters are located near the genes they regulate, on the

same strand and typically upstream (towards the 5' region of

the sense strand).


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Cis-acting elements - DNA sequences in the

vicinity of the structural portion of a gene that

are required for gene expression

Trans-acting factors - factors, usually

considered to be proteins, that bind to the cis-

acting sequences to control gene expression


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Eukaryotic Promoters

CAP site TAC


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Core promoters:

Core promoters are Minimal promoters thatcontain TATA box.

The TATA box is also called Goldberg-Hogness box.

These DNA sequences are (cis-elements) foundin archaea and eukaryotes

TATA box is essential for RNA polymerase II-dependent transcription

Located at about -20 t0 -35 bp upstream fromtranscription start site.


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Types of Promoters

Constitutive promoters:

Inducible promoters:

Tissue-specific promoters :

Synthetic promoters:


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Constitutive promoters

They facilitate expression of the gene in all tissues

regardless of the surrounding environment and

development stage of the organism

They are active in all circumstances in the cell.

Examples:Plant pathogen/Dicot promoters

Opine promoters

CaMV 35S promoterMonocot promoters

Plant ubiquitin promoter (Ubi)

Rice actin 1 promoter (Act-1)

Maize alcohol dehydrogenase 1 promoter (Adh-1)


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Inducible promoters

which are only expressed under the presence offactors /compounds.

They may be Chemically or Physically induced

Types & Example:Chemically induced

1. Alcohol-regulated:

2. Tetracycline-regulated:

3. Steroid-regulated:

4. Metal-regulated:

5. Pathogenesis-relatedPhysically induced

1. Temperature-regulated promoters

2. Light-regulated promoters


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Tissue Specific Promoters

which operate in particular tissues and at certaindevelopmental stages of a plant.

They may be induced by endogenous and exogenous

factors.

Root Promoters ,Fruit Promoters ,Seed Promoters etc.

Example:

Phosphoenolpyruvate (PEP) carboxylase promoter

which induces gene expression only in cells that are

actively involved in photosynthesis


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Synthetic Promoters:

Promoters made by bringing together the

primary elements of a promoter region from

diverse origins.

Chimeric genes form through thecombination of portions of one or more coding

sequences to produce new genes

By fusing the promoters of two different genes

into one chimeric gene.


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1.Promoters and UAS from opine synthase genes:

Patents granted in the U.S. and Australia directed to promotersand Upstream Activating Sequences (UAS) derived from

opine synthase genes, specially from the ocs and mas genes of

A. tumefaciens;

2. 35S-enhanced maspromoter:

Patents granted in the U.S. and Canada directed to a mas

promoter enhanced by a UAS from CaMV 35S gene

Mannopine synthase (mas)


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CaMV 35S Promoter

1. Caulifl ower mosaic virus(CaMV) replicate through reversetranscription just like retroviruses, but the viral particles

contain DNA instead of RNA.

2. The promoter of the 35S RNA is a very strong constitutive

promoter responsible for the transcription of the whole

CaMV genome.

3. Most widely used promoter in plant gene transfer.

4. Drives high level of expression in dicots

5. Its ideal for driving expression of selectable marker genes

and in some cases of reporter genes.


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Inducible Promoters:


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Inducible Promoters:

The activity of these promoters is induced by

the presence of biotic or abiotic factors.

The expression of genes operably linked to them

can be Turned On or Offat certain stages of

development of an organism or in a particulartissue.


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Desirable features of a inducible

promoters:

1. No expression of Trans Gene in the absence ofinducer

2. It should be specific to inducer- only one or one

class of inducer.3. The inducer should be non toxic

4. Induction of gene expression should be rapidfollowing the application of inducer

5. Induction of gene expression should ceaserapidly following the withdrawal of inducer


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Types of inducible promoters:

Three types:

1. Non plant derived systems

2. Plant derived systems that respond to

environmental signals

3. Plant derived systems based on developmental

control of gene expression.


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1. Non plant derived systems

A. Tetracycline

B.Ethanol Inducible

C.Steroid Inducible

D.Copper Inducible


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A. Tetracycline Tetracycline is used to either De- Repress Or Inactivate

Gene Expression

De- repression:

Tetracycline repressor (TetR) binds to tet operator- negative

regulation

Tetracycline act as a inducer- activation / de

repression.

Inactivation:

TetR is modified to an activator called Tetracycline Trans-

activator (tTA). tTA binds to operators and induces gene expression in absence of

tetracycline

When Tetracycline is present , tTA is released and expression

ceases.


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Alcohol inducer: The ethanol utilization pathway of the filamentous fungus

Aspergillus nidulans is a well-characterized positive operon system.

It controls the cellular response to ethanol and other related

chemicals.

The first enzyme in the pathway is Alcohol Dehydrogenase I

encoded by the alcA gene.

The transcriptional activator protein AlcR binds target sequences

within the alcA gene promoter in the presence of ethanol, ethyl

methyl ketone or other alcohols/ketones.

These compounds act as inducers of the gene expression.


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Alcohol inducer: This system uses Chimeric promoters

core 35S promoter

region + promoter containing binding sites ofAlcR

Transcription factor from Aspergil lus nidulans

This allows constitutive expression.

Ethanol act as a inducer-AlcR binds to promoters and

activates transcription

Syngenta has several patents and patent applications in

Europe and Australia directed to the transcriptional system

containing the alcohol dehydrogenase I (alcA) gene promoter


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Steroid Inducible

Modified transcription factor capable of binding with steroidinducer acts as activator of chimeric promoters

The mammalian Glucocorticoid Receptor (GR) is a member

of the family of animal steroid hormone receptors.

GR also acts as a transcription factor by activating genetranscription from promoters containing Glucocorticoid

Response Elements (GRE)

A system comprised of the GR and GREs resulted in transient

expression in tobacco

Dexamethasone, a strong synthetic glucocorticoid used asinducer.

Oestrogen and ecdysone are other inducers


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Steroid Inducible

Numerous patent and patent applications are

directed to steroid-responsive promoters for

the modulation of gene expression in plant

and animal cells

McGill University patents on promoters based

on the Rat Glucocorticoid Receptor (GR);

Rockefeller University patents on promoters

based on the Human Estrogen Receptor (ER);


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Copper Inducible

This system is based on Metallothionein genes

from yeast.

Upon binding Copper, the transcription factor

binds to Chimeric Promoter and activates theexpression.

Promoters derived from Metallothionein genes

from yeast, mouse and human are the subjectmatter of several United States patents granted

to Genentech and University of California


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2. Plant derived systems that

respond to environmental signals

Wound inducible

Heat shock inducible


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1. Wound inducible

The nos promoter (nopaline synthase) is wound inducible

in both vegetative and reproductive organs.

The induction of the nos promoter was observed in leaves,

stems, cotyledons, and various reproductive organs,

suggesting that the response is not organ specific.

The wound response was further enhanced by addition of

auxins.

Nopaline synthase promoter is wound inducible and auxin inducible. G An, M A

Costa and S B Ha (http://www.plantcell.org/content/2/3/225.abstract)
http://www.plantcell.org/content/2/3/225.abstracthttp://www.plantcell.org/content/2/3/225.abstract


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Wound inducible

The promoter, found in potato plants, regulatesa gene encoding the serine-type proteinaseinhibitor II (PinII).

PinII is constitutively expressed only in tubersand young floral buds of potatoes

PinII expression can be induced by mechanicalwounding in leaves

Methyl- jasmonate mimic wounding-as inducer

Used fro expression of pest resistant genes

http://myip.cctec.cornell.edu/techdocs/D1155.D1155_Wound_Inducible_Promoter_

Tech_Brief.pdf
http://myip.cctec.cornell.edu/techdocs/D1155.D1155_Wound_Inducible_Promoter_Tech_Brief.pdfhttp://myip.cctec.cornell.edu/techdocs/D1155.D1155_Wound_Inducible_Promoter_Tech_Brief.pdfhttp://myip.cctec.cornell.edu/techdocs/D1155.D1155_Wound_Inducible_Promoter_Tech_Brief.pdfhttp://myip.cctec.cornell.edu/techdocs/D1155.D1155_Wound_Inducible_Promoter_Tech_Brief.pdf


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2. Heat shock inducible

HEAT SHOCK ELEMENT(HSE) MEDIATED HEAT SHOCK INDUCIBILITY

Soybean heat-shock promoter Gmhsp17.3

Temp. shock of - 400 C produced 10k to 20k nbr of copies of

heat shock protein The promoter of the HSP18.2 gene from Arabidopsis, encoding a

heat shock protein, indicated that it functions as a strong

inducible system in plants

1. Comparison of different constitutive and inducible promoters for the overexpression of

transgenes in Arabidopsis thaliana.Holtorf S, Apel K, Bohlmann H.(

http://www.ncbi.nlm.nih.gov/pubmed/8541491 )

2. Gene silencing using a heat-inducible RNAi system in Arabidopsis (http://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdf)

3 Plant derived systems based on
http://www.ncbi.nlm.nih.gov/pubmed?term=Holtorf%20S[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Apel%20K[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Bohlmann%20H[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed/8541491http://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdfhttp://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdfhttp://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdfhttp://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdfhttp://hal.archives-ouvertes.fr/docs/00/11/95/62/PDF/BBRC_HAL.pdfhttp://www.ncbi.nlm.nih.gov/pubmed/8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Bohlmann%20H[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Bohlmann%20H[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Bohlmann%20H[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Apel%20K[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Apel%20K[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Apel%20K[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Holtorf%20S[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Holtorf%20S[Author]&cauthor=true&cauthor_uid=8541491http://www.ncbi.nlm.nih.gov/pubmed?term=Holtorf%20S[Author]&cauthor=true&cauthor_uid=8541491


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3. Plant derived systems based on

developmental control of gene

expression

Senescence Specific Gene Expression

ABA Inducible Gene Expression

Auxin Inducible Gene Expression


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Senescence Specific Gene Expression Senescence inducible promoters fromArabidopsis genes- SAG12 & SAG13( Senescence

Associated Gene)

An ipt gene(isopentenyltransferase) undercontrol of the senescence

specific SAG12 promoter significantly

delayed developmental and postharvest leaf

senescence in mature heads of transgenictobacco .

Similar result in In lettuce

n uc e ene


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n uc e eneExpression

Abscisic Acid (ABA), an inexpensive, non-toxic,

natural substance can be used as a highly effective

chemical inducer

ABA is mediates a wide variety of stress responses

in plants and induces abscission in leafs during thefall season of the year.

Eg: The promoter of the barley ABA-responsive

HVA22 gene

Functional dissection of an abscisic acid (ABA)-inducible gene reveals two

independent ABA-responsive complexes each containing a G-box and a novel

cis-acting element.(http://www.ncbi.nlm.nih.gov/pubmed/7734964)

A i I d ibl G
http://www.ncbi.nlm.nih.gov/pubmed/7734964http://www.ncbi.nlm.nih.gov/pubmed/7734964


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Auxin Inducible Gene

Expression

Auxin plays an essential role in a wide variety of plant growthand developmental processes, such as shoot and lateral rootformation, apical dominance, tropism, and senescence

A large number of auxin-inducible genes have been clonedand characterized, includingArabidopsis, soybean

hypocotyls, pea epicotyls etc

Examples:

1. The auxin-inducible soybean GH3 gene

2. ARGOS, a novel auxin- inducible gene that is involved in

organ size control inArabidopsisAuxREs( auxin response elements) combined with 35S core

promoter


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Reference:

1. Plant Biotechnology-The genetic manipulation of plants

by Adrian Slater and others

2. Introduction to Plant Biotechnology, by H. S. Chawla

3. Cellular And Biochemical Science edited by G. Tripathi

plant promoters

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