2What are they?Short sequences (between 4 and 13-ish nucleotides) – one might even say they’re very shortOccur multiple times in the genome, at dispersed intervals (not repeated right next to each other) – “distributed or spread over a wide interval”
3It turns out that many of these very short dispersed sequences are palindromic – what does that mean?The sequence is read the same in the 5’ 3’ direction as it is in the 3’ 5’ direction.
4Occurrence of Highly Iterated Palindromes (HIP1) in Cyanobacteria
5Palindromic Sequence in Cyanobacteria 5’-GCGATCGC-3’ 3’-CGCTAGCG-5’ But not all cyanobacteriahave this sequence
10Results?Hypothetical Proteins-highest peak in Themosynechococcus and TrichodesmiumMany metabolic proteins such as Ferredoxin, peptidaseProgram to overlap nearby genes in different organisms
11ReferencesRobinson, P. J., Cranenburgh, R. M., Head, I. M. and Robinson, N. J. (1997), HIP1 propagates in cyanobacterial DNA via nucleotide substitutions but promotes excision at similar frequencies inEscherichia coli and Synechococcus PCC Molecular Microbiology, 24: 181–189. Robinson, P. J., Gupta, A., Bleasby, A., Whitton, B., Morby, AP. Singular over- representation of an octameric palindrome, HIP1, in DNA from many cyanobacteriaMoya, A. Delaye, L. Abundance and distribution of the highly iterated palindrome 1(HIP1) among prokaryotes Mob Genet Elements Sep-Oct; 1(3)
12Occurrences of DNA uptake sequence from Haemophilus influenzae in other Pasteurellaceae bacteria By: Noha Mudhaffar
16Actinobacillus-succinogenes-130Z 1690 Haemophilus-influenzae-86-028NP OrganismLengthGC-FRACTIONOccurrences of DNA USSActinobacillus-succinogenes-130Z1690Haemophilus-influenzae NP1516Actinobacillus-actinomycetemcomitans-HK16511507Mannheimia-succiniciproducens-MBEL55E1485Haemophilus-influenzae-R28461461Haemophilus-somnus-23361355Haemophilus-somnus-129PT1245Haemophilus-influenzae-R2866952Pasteurella-multocida-subsp-multocida-str-Pm70927Haemophilus-influenzae-86028NP888Haemophilus-influenzae-Rd-KW20737Actinobacillus-pleuropneumoniae-L2073Actinobacillus-pleuropneumoniae-serovar-1-str-407463Mannheimia-haemolytica59Haemophilus-ducreyi-35000HP41
17OrganismLengthGC-FRACTIONOccurrences of DNA USSEscherichia-coli-DH10B19Escherichia-coli-5363822Escherichia-coli-HS5Escherichia-coli-E24377AEscherichia-coli-E18Escherichia-coli-F11Escherichia-coli-04224Escherichia-coli-E11001917Escherichia-coli-K1223Escherichia-coli-O157-H727Escherichia-coli-B7A15Escherichia-coli-APEC-O114Escherichia-coli-B171Escherichia-coli-CFT0737Escherichia-coli-W3110Escherichia-coli-E22Escherichia-coli-O157-H7-EDL93310Escherichia-coli-ATCC-8739
18ReferenceFrequency and Distribution of DNA Uptake Signal Sequences in the Haemophilus influenzae Rd Genome.Genomic Sequence of an Otitis Media Isolate of Nontypeable Haemophilus influenzae: Comparative Study with H. influenzae Serotype d, Strain KW20.Xu Z, Yue M, Zhou R, Jin Q, Fan Y, et al. (2011) Genomic Characterization of Haemophilus parasuis SH0165, a Highly Virulent Strain of Serovar 5 Prevalent in China. PLoS ONE 6(5): e doi: /journal.poneDNA uptake signal sequences in naturally transformable bacteria.
19The Evolutionary Change of DNA Uptake Sequences in Neisseria meningitides.
20What are DNA Uptake Sequences (DUS)? Neisseria sp.Constitute ~1% of genome.Homology5’GCCGTCTGAA’3Kingdom: BacteriaPhylum: ProteobacteriaClass: BetaproteobacteriaOrder: NeisserialesFamily: NeisseriaceaeGenus: NeisseriaSpecies:Neisseria meningitidis
25References http://phil.cdc.gov/phil/details.asp?pid=2678 Frye SA, Nilsen M, Tønjum T, Ambur OH. Dialects of the DNA uptake sequence in Neisseriaceae. PLoS Genet. 2013
26Six nucleotide palindromic sequences in Mycobacteriophage genomes What about them? That’s a great question. I’m glad you asked.
27How did we get here from Very Short Dispersed Repeats How did we get here from Very Short Dispersed Repeats? A very short story.Point A:“Singular over-representation of an octameric palindrome, HIP1, in DNA from many cyanobacteria.”From there: what about palindromes in mycobacteriophages??
28Avoidance of 6 nt palindromes in Mycobacteriophages Mycobacterial genomes generally do not avoid 6 palindrome sequence. Generally, this means that the viruses that infect them will not either. When two of the mycobacteriophage genomes were examined, they were found to avoid palindromes of size 6. “The sole exception is provided by the two M. tuberculosis phages D29 and L5, which strongly avoid palindromes of size 6.” (Rocha, et. al) 2001 L5 and D29 – Mycobacteriophage cluster A2
29Generated 186 random sequences of the same length of the average Mycobacteriophage genome (70627 nucleotides long) and same GC content (64%) and counted the number of occurrences of all 6 nucleotide palindromes in these randomly generated sequences.
30Occurrences of all 6 nucleotide palindromes over the actual genomes of Mycobacteriophages (or at least the 186 that BioBIKE knows)
31All of the cluster C1 phages in BioBIKE! Which phages are outliers to the right? (>2000 occurrences) - these 15All of the cluster C1 phages in BioBIKE!((Mycobacterium-phage-Cali 2485) – C, C1 (Mycobacterium-phage-Catera 2466) – C, C1 (Mycobacterium-phage-Alice 2437) – C, C1 (Mycobacterium-phage-LRRHood 2445) – C, C1 (Mycobacterium-phage-Rizal 2465) – C, C1 (Mycobacterium-phage-Nappy 2528) – C, C1 (Mycobacterium-phage-Ghost 2524) – C, C1 (Mycobacterium-phage-Drazdys 2506) – C, C1 (Mycobacterium-phage-ScottMcG 2480) – C, C1 (Mycobacterium-phage-Spud 2485) – C, C1 (Mycobacterium-phage-Sebata 2519) – C, C1 (Mycobacterium-phage-Pio 2505) - C, C1 (Mycobacterium-phage-Bxz1 2501) – C, C1 (Mycobacterium-phage-LinStu 2478) – C, C1 (Mycobacterium-phage-ET )) – C, C1
32What’re C1 cluster phages? “Only two of these (Subclusters C1 and C2) correspond to phages with myoviral morphologies (with contractile tails)”Okay, so they’re of the family Myoviridae. This means they are: generally lytic, and lack the necessary genes to become lysogenic. They have a contractile tail, and contracting the tail requires ATP.C cluster phage isolated by Michael Kiflezghi!
33Which sequences are occurring so frequently? GGCGCC GACGTC CGCGCG ACCGGTGTCGAC GCGCGC CCCGGGTGGCCA CAGCTG AGGCCTCGATCG CTGCAG TGCGCAMany of these are recognition sites for restriction enzymes. Significant? There’s a chance.Warrants more investigation? It seems likely.
34References and credit for pictures phagesdb.orgRocha, E., Danchin, A., & Viari, A. (2001). Evolutionary role of Restriction/Modification systems as revealed by comparative genome analysis. Genome Research, (11), doi: /gr Discussion of avoidance of palindromic sequences of length 4 and 6 and possible reasons for this avoidance in bacteria and bacteriophages. Mentions 2 mycobacteriophages that exhibit an avoidance for 6nt palindromes, L5 and D29.Article Source: Expanding the Diversity of Mycobacteriophages: Insights into Genome Architecture and Evolution. Pope WH, Jacobs-Sera D, Russell DA, Peebles CL, Al-Atrache Z, et al. (2011) Expanding the Diversity of Mycobacteriophages: Insights into Genome Architecture and Evolution. PLoS ONE 6(1): e doi: /journal.ponecyanobacteria picture:mycobacteriophage picture:coral snake: