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Exploring the rns gene landscape in ophiostomatoid fungi and related taxa: Molecular characterization of mobile genetic elements and biochemical characterization of intron-encoded homing endonucleases.

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dc.contributor.supervisor Hausner, Georg(Microbiology) en_US
dc.contributor.author Abdel-Fattah, Mohamed Hafez
dc.date.accessioned 2012-07-27T19:46:57Z
dc.date.available 2012-07-27T19:46:57Z
dc.date.issued 2011 en_US
dc.date.issued 2011 en_US
dc.date.issued 2012 en_US
dc.identifier.citation Fungal Biology, 115: 1122-1137 en_US
dc.identifier.citation World Academy of Science, Engineering and Technology, 59: 1767-1775 en_US
dc.identifier.citation Fungal Biology, 116: 98-111 en_US
dc.identifier.uri http://hdl.handle.net/1993/8130
dc.description.abstract The mitochondrial small-subunit ribosomal RNA (mt. SSU rRNA = rns) gene appears to be a reservoir for a number of group I and II introns along with the intron- encoded proteins (IEPs) such as homing endonucleases (HEases) and reverse transcriptases. The key objective for this thesis was to examine the rns gene among different groups of ophiostomatoid fungi for the presence of introns and IEPs. Overall the distribution of the introns does not appear to follow evolutionary lineages suggesting the possibility of rare horizontal gains and frequent loses. Some of the novel findings of this work were the discovery of a twintron complex inserted at position S1247 within the rns gene, here a group IIA1 intron invaded the ORF embedded within a group IC2 intron. Another new element was discovered within strains of Ophiostoma minus where a group II introns has inserted at the rns position S379; the mS379 intron represents the first mitochondrial group II intron that has an RT-ORF encoded outside Domain IV and it is the first intron reported to at position S379. The rns gene of O. minus WIN(M)371 was found to be interrupted with a group IC2 intron at position mS569 and a group IIB1 intron at position mS952 and they both encode double motif LAGLIDADG HEases referred as I-OmiI and I-OmiII respectively. These IEPs were examined in more detail to evaluate if these proteins represent functional HEases. To express I-OmiI and I-OmiII in Escherichia. coli, a codon-optimized versions of I-OmiI and I-OmiII sequences were synthesized based on differences between the fungal mitochondrial and bacterial genetic code. The optimized I-OmiI and I-OmiII sequences were cloned in the pET200/D TOPO expression vector system and transformed into E. coli BL21 (DE3). These two proteins were biochemically characterized and the results showed that: both I-OmiI and I-OmiII are functional HEases. Detailed data for I-OmiII showed that this endonuclease cleaves the target site two nucleotides upstream of the intron insertion site generating 4 nucleotide 3’overhangs. en_US
dc.publisher ELSEVIER en_US
dc.publisher World Academy of Science, Engineering and Technology en_US
dc.publisher ELSEVIER en_US
dc.rights info:eu-repo/semantics/openAccess
dc.subject Mitochondrial genome en_US
dc.subject Mobile introns en_US
dc.subject Homing endonucleases en_US
dc.subject mt. SSU rRNA gene en_US
dc.subject Twintron en_US
dc.subject reverse transcriptase en_US
dc.title Exploring the rns gene landscape in ophiostomatoid fungi and related taxa: Molecular characterization of mobile genetic elements and biochemical characterization of intron-encoded homing endonucleases. en_US
dc.type info:eu-repo/semantics/doctoralThesis
dc.type doctoral thesis en_US
dc.degree.discipline Microbiology en_US
dc.contributor.examiningcommittee Court, Deborah (Microbiology) Oresnik Ivan (Microbiology) Piercey-Normore, Michele (Biological Sciences) Hintz, William (University of Victoria, Canada). en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note October 2012 en_US


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