Gene Expression during Heterocyst Differentiation - Advances in Botanical Research - page 278

CHAPTER EIGHT

Gene Expression during
Heterocyst Differentiation

Antonia Herrero * , Silvia Picossi, Enrique Flores
Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
*Corresponding author. E-mail: [e-mail]

Contents
1. Introduction

282

2. TheHeterocyst 284

2.1. TheHeterocystsareSitesofNitrogenFixation 284

2.2. TheHeterocystEnvelope 285

2.2.1. Chemical nature 285

2.2.2. Biosynthesis and deposition 287

2.2.3. Function 288

2.3. TheHeterocystCytoplasmandHeterocystMetabolism 289

2.3.1. Carbon metabolism 289

2.3.2. Bioenergetics 290

2.3.3. Nitrogen metabolism 291

2.4. IntercellularMolecularExchange 292

3. TheSpeciicProgramofGeneExpression 293

3.1. TriggeringoftheDiferentiationProcess 293

3.2. GenesActivatedTransientlyduringDiferentiationwithSpatialSpeciicity 294

3.3. GenesActiveintheMatureHeterocyst 296

3.4. GenesRepressedduringDiferentiation 297

3.5. GlobalStudiesofGeneExpression 297

3.5.1. Microarray analysis in Anabaena sp. strain PCC 7120 298

3.5.2. Directional RNA sequencing in Anabaena sp. strain PCC 7120 299

3.5.3. Transcription start point mapping in Anabaena sp. strain PCC 7120 299

3.5.4. Microarray analysis in Nostoc punctiforme 306

4. MechanismsofGeneRegulationduringHeterocystDiferentiation 308

4.1. TheNtcAandHetRRegulators 308

4.2. ComplexPromoterRegionsinHeterocystGenes 310

4.3. OtherRegulatorsCo-operatinginGeneActivation 314

4.4. RegulatorsImpactingthePatternofHeterocystDistribution 316

4.4.1. PatS and HetN 316

4.4.2. Other elements influencing heterocyst distribution 317

5. ConclusionsandPerspectives 318