Do Cyanobacteria Communicate With Each Other?

Bacterial Communication Quorum Sensing Important to perform group functions Secretion of toxins to kill competitors, production of luminescent compounds, etc. Small numbers of bacteria don’t activate their Quorum Sensing genes

Bacterial Communication Quorum Sensing Gram negative bacteria secrete acylhomoserine lactone (AHL) quorum sensing signals also called Autoinducers (AI’s) These molecules can easily diffuse through the membrane and are detected by proteins in the cytoplasm In this way the gram negative bacteria can communicate with each other When concentration of AI’s is high enough (numbers of bacteria are high enough) it can trigger genes to become expressed

Bacterial Communication Vibrio fischeri Hawaiian Bobtailed Squid Euprymna scolopes Light Organ Containing Vibrio fischeri

Cell Density Time growth bioluminescence Induction of Bioluminescence in Vibrio Fischeri (Auto-induction)

Auto-induction in Vibrio Fischeri LuxI AHL’s LuxR luxCluxDluxAluxBluxE

Auto-induction in Vibrio Fischeri LuxI AHL’s LuxR luxCluxDluxAluxBluxE luciferase Autoinducer binds LuxR activated Moves to promoter of luciferase genes

Gram Positive Communication Gram positive bacteria secrete small oligopeptides as their signal molecule The other bacteria have receptors for the signal peptides (also called auto-inducers) When the receptor binds the signal peptide it triggers the target genes

Gram Positive Quorum Sensing ABC (ATP binding cassette) transporter Recognizes GG containing sequence, Cleaves the peptide, and secretes it GG P P sensor kinase - binding of autoinducer leads to autophosphorylation at conserved histidine residue response regulator - phosphorylation leads to binding of regulator to specific target promoters His P D ACTTTGCGATTGGCC Peptide signal Precursor genes Precursor peptide Final Peptide Signal

How do you find what type of signaling cyanobacteria use? Are they similar to the gram positive bacteria? The gram negative? Or something entirely different?

Do Cyanobacteria use gram negative type signaling? The LuxI protein in Vibrio fischeri has a specific motif [LMFYA]-R-x(3)-F-x(2)-[KRQ]-x(2)-W-x- [LIVM]-x(6,9)-E-x-D-x-[FY]-D Search proteins of cyanobacteria for this motif = nil

Do Cyanobacteria use gram negative type signaling? Use Pfam to find the sequence of proteins related to Luxi Use conserved sequences to create a PSSM to compare with cyanobacterial proteins

Q9ZIU1_BURCE/10-189Q9ZIU1_BURCE/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM57_BURCE/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM55_BURCE/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM54_9BURK/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DGRLV.VAC.. Q93PD3_BURVI/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DG Q93PF8_BURCE/ NAEWAVRP..ML.AA.AVECAAQLGARQLIGVTFASMERLFRRIG-IHAHRA..G..PPK....q-V.DG Q9AER2_9BURK/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM52_BURCE/ NAEWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM53_BURVI/ NADWAVRP..ML.AV.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q93PF5_9BURK/ NADWAVRP..ML.AA.VVECAAQLGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DG Q9AM56_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM45_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASKERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM44_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q93NN9_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM42_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q9AM43_BURML/9-189.GADWAVRP..ML.AA.VVACAAERGARQLIGVTFASMERLFRRIG-VHAHRA..G..PPK....q-V.DGRLV.VAC.. Q8L2M9_BURPS/ NLAWAVRP..ML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRT..G..PAQ....q-I.DGRMV.VAC.. Q8KRT8_BURMA/ GGNPAWAVrpML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC.. Q6UBQ0_BURPS/ GGNPAWAVrpML.AA.VVECAARLGAKQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC.. Q6Q6F8_BURTH/ TGNPAWAVrpML.AA.VVECAARLGARQLIGVTFLSMERLFRRIG-VHAHRA..G..PAQ....q-I.DGRMV.VAC.. SOLI1_RALSO/ RPDWAVRP..ML.AS.VVQCAAQRGARRLIGVTFVSMVRLFRRIG-VRAHHA..G..PVR....c-I.GGRPV.VAC.. SOLI2_RALSO/ RADWAVRP..ML.AS.VVQCAAQRGARRLIGATFVSMVRLFRRIG-VRAHRA..G..PVR....c-I.GGRPV.VAC.. Q9AHP8_BURCE/9-191.ESWQNTRA..MM.SE.IVRVAHAHGANRLIAFSVLGNERLLKRMG-VNVHRA..A..PPQ....m-I.EGKPT.LPF.. Q9AM57_BURCE/ Q9AM55_BURCE/ Q9AM54_9BURK/ Q93PD3_BURVI/ Q93PF8_BURCE/ Q9AER2_9BURK/ Q9AM52_BURCE/ Q9AM53_BURVI/ Q93PF5_9BURK/ Q9AM56_BURML/9-189 Q9AM45_BURML/9-189 Q9AM44_BURML/9-189 Q93NN9_BURML/9-189 Q9AM42_BURML/9-189 Q9AM43_BURML/9-189 Q8L2M9_BURPS/ Q8KRT8_BURMA/ Q6UBQ0_BURPS/ Q6Q6F8_BURTH/ SOLI1_RALSO/ SOLI2_RALSO/ Q9AHP8_BURCE/9-191 Pfam search results for LuxI Alignment of Conserved sequences for autoinducer synthase (LuxI like proteins)

Comparison of s7942 protiens against Luxi-PSSM (#$S7942.p-Ser0724 (19 "LLQAASGLGAGLIVV" ) (208 "RLAHWLDRGYSQIAV" ) (#$S7942.p-Ser1616 (44 "AVLTAAPSSAAERIT" ) (294 "HVTTSARSFENVLVG" ) (409 "VAAVAADGLASDVFG" ) (431 "TVPTLIWGGSRDVVT" ) (#$S7942.p-Ser2323 (65 "IRKWNRELDYRLIKE" ) (77 "IKEVWAWHDNRIAVR" ) (#$S7942.p-Sef2443 (51 "TGKPAWELRTPQIVY" ) (307 "SAKDQARLQANRLIW" ) (#$S7942.p-Sef2642 (5 "WVRCARLLKLCFCTA" ) (132 "VGEVAAERLTPAIAT" ) (#$S7942.p-SSELR002 (146 "IVASSSLNGIQQVVK" ) (206 "NTAIAGGHGLTNSIT" ) (229 "LIEYLVESGLPQDMA" ) Results Name of protein, starting position of sequence, sequence, score

Do cyanobacteria use gram positive type signaling The peptides used in gram positive bacteria have a conserved GG leader sequence which allows them to be secreted by their ABC transporter This GG containing sequence has its own motif as well LSX2ELX2IXGG Searching cyanobacteria for this motif = nil

Possible GG containing sequences found in other experiments Do cyanobacteria use gram positive type signaling Peptide signal molecules and bacteriocins in Gram-negative bacteria: a genome-wide in silico screening for peptides containing a double-glycine leader sequence and their cognate transporters by G. Dirixa, P. Monsieursb, B. Dombrechta, R. Danielsa, K. Marchalb, J. Vanderleydena, J. Michielsa,. MRELTLTEIDNVSGA MKELTQTEVMEVSGA NEELSTDELKSVSGG LQELSFDEIDQVSGA SQELSPQELANISGG IRELNEAELNCICGG TRELTENELEMTAGG FKELKENELTAITGG LKDLSEKELAAVFGG LQELTPEELEQIAGG LQELSTEELEQIAGG MQELSEEQLQATAGG MLELSNQELDYIAGG RQTLSDDELESVAGG RQTLSEDELESVAGG RQTLSDRELEGVAGG GRELSEEELESVAGG PIELSAEELDNVAGG PVELSAEELDNVAGG MKELHTSELVEVSGG MKELNDIEVTCVSGG MIELQLHELKLVSGG MRELTSNEMNNVSGG MRELTSIEMNNVSGG MRELTSYELQAVSGG MRTINDVEMEEVSGG MRTINAAEMEEVSGG MRTLTLNELDSVSGG MRELAFQEIENVDGA MRELVIQEIESVDGG VRELTVREIESVDGG MRELSKVEIEQISGA MRTELEIHEIESIGGA MRKLSENEIKQISGG MREITESQLRYISGA MREISQKDLNLAFGA MRELDREELNCVGGA LFINLSDEQQAFVAG LFINLSDEQQAFVAG LFMNLSDEQQAVVKG LFINLSDTQQAVVTG LFRNVSLEQQEMVVG LLADLSTEQQQFLVG LLEDLSLDQQQSLAG LLVELSTEDQQNLAG YLQDLSEQEQEIICG LFIDIYPEKSESVSG LFTQISVEESGVAAG EQDTLSEAELESVAG

Comparison of s7942 proteins against GG-PSSM (#$S7942.p-Sef MQHLVDGDLAANNGG)#$S7942.p-Sef1302 (#$S7942.p-Ser MEERMTVCNMAIEGG)#$S7942.p-Ser0408 (#$S7942.p-Sef LGPEASSVIQSIAGG)#$S7942.p-Sef2007 (#$S7942.p-Ser AEKMMQAAWQEISGG)#$S7942.p-Ser0406 (#$S7942.p-Ser YEQLLAPIYEWMAGG)#$S7942.p-Ser1379 (#$S7942.p-Sef0291 ( FLSLLSRDQVQWQGG) (#$S7942.p-Ser0724 ( RQVVVHRHLGAMLGG) ( LRQLPLDALGLVFGG) This protein comes from an unknown gene it is small Like most Peptide signal molecules (less than 300 aa’s) So it could be a likely candidate for an autoinducer

Do cyanobacteria communicate with eachother? It would be beneficial for them to do so in some cases Tricodesmium grows in clusters Fixes N 2 But not with heterocysts Cells in middle of the clusters are Surrounded by much less O 2 than those Outside the clusters Thus N 2 fixation can occur in this organism

Do cyanobacteria communicate with each other? Cant give a definate answer based on these results However there are sequences similar to both types of Autoinducers present in the proteins of cyanobacteria

What I would do differently Screen nucleotides instead of proteins Look for nearby ABC transporters for the possible GG-hits Search more cyanobacteria for quorum sensing systems

Thanks to colaborators Rakefet Schwarz Bar llan University Alex from Bar llan university Yitschak Friedman Jeff Elhai VCU