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Positional cloning of the Hybrid sterility 1 gene: fine genetic mapping and evaluation of two candidate genes
Mihola, Ondřej ; Trachtulec, Zdeněk (advisor) ; Munclinger, Pavel (referee) ; Pravenec, Michal (referee)
Summaryofpublications 1. Positionalcloningof the Hybridsterility1 gene:finegenetic mappingand evaluationof twocandidategenes Hybridsteri|iýis one of the mechanismsof speciation.The Hybridsteriliý1 (HsÍí)genewasthefirstmappedmammaliangene.The geneaffectsfertiliýof male hybridsbetweencertainlaboratorystrains(suchas C57Bl/10)and Mus musculus musculusmiceby causinga breakdownof spermatogenesisat thestageof primary spermatocytes.|ntheprocessof positiona|c|oningoftheHsÍígene,Wegenerateda contigof bacterialartificialchromosomes(BACs)and subsequentlya lowcoverage sequenceof the candidateregionof the '12951/SvlmJstrain.New geneticmarkers narroweddown the HsÍíregionfrom 580 to 360 ki|obases.The productsof two genesfromthisregion,TATA-bindingprotein(Ibp)and proteasomesubunitbeta1 (Psmb1\,accumulateduringspermatogenesis.The proteinshave been described previouslyas having conservedC{erminal sequencesand species-specificN- termini.We eva|uatedthe candidacyof thesegenesfor Hsťíby a||e|icsequencing and by real-timereverse-transcriptionPCR of testicularmRNAs.The resultssuggest thatneitherthePsmÓí northe lbp genecausehybridsteri|ity.Thesing|enuc|eotide po|ymorphisms(SNPs)we havefound,was usedfor the hap|oýpeana|ysisof the HsÍíregion.
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The role of histone modifications and gene expression in mouse spermatogenesis
Křivánková, Klára ; Mihola, Ondřej (advisor) ; Jansa, Petr (referee)
The production of haploid sperm is a precondition for sexual reproduction of males. PRDM9 protein is a histone methyltransferase which localizes sites of meiotic recombination in many mammals. Mouse males of the C57BL/6J (B6) strain deficient for Prdm9 (Prdm9-/- ) are sterile, while Prdm9-/- males of PWD/Ph (PWD) strain have reduced sperm count. The comparison of the distribution of trimethylation of histone 3 on lysine 36 (H3K36me3) in genome of Prdm9-/- males of these two strains will help to determine the role of this epigenetic modification on meiotic recombination and fertility of Prdm9-/- males. The second part of this thesis is focused on transgenic males. Male offspring from the first generation of B6 female and PWD male crosses (B6PF1) have reduced fertility parameters due to incompatibility of Prdm9 alleles. The fertility parameters of B6PF1 hybrids carrying CHORI-34-289M8 or RP24-346I22 transgene are even lower. The candidate gene, which participates in the reduction of fertility of the transgenic B6PF1 hybrids, was determined as the proteasome subunit encoding gene Psmb1, because its relative transcription level best correlates with sperm count. The reason of lowered fertility thus might be a defect in proteasome assembly. The investigation of the fitness of transgenic animals is...
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The role of H3K36 methylation in DNA repair of germinal and somatic cells
Křivánková, Klára ; Mihola, Ondřej (advisor) ; Schierová, Michaela (referee)
Histone modifications affect many cellular processes including DNA damage repair. This thesis focusses on the methylation of lysine 36 of histone 3 (H3K36). The role of this modification in the localization of DNA double-stranded breaks in germinal cells is described in the first part of this thesis. Double-stranded breaks initiate meiotic recombination, which is essential for successful meiosis. This thesis also describes three histone methyltransferases. The first is PRDM9, an enzyme expressed only in oocytes and spermatocytes during meiotic prophase and responsible for the localization of recombination hotspots in most mammals. The second part of this thesis deals with the role of H3K36 methylation in DNA damage repair in somatic cells using homologous recombination (HR) and nonhomologous DNA ending joining (NHEJ). The proteins SETD2 and SETMAR are described in the second part. SETD2 trimethylates H3K36, and H3K36me3 is recognized by the LEDGF protein. Through LEDGF, other components necessary for HR are recruited to DNA. SETMAR dimethylates H3K36 and together with this histone modification promote DNA break repair with NHEJ. The research of H3K36 methylation is important for a better understanding of each DNA repair mechanisms. The correct repair of DNA breaks is necessary for maintaining...
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Positional cloning of the Hybrid sterility 1 gene: fine genetic mapping and evaluation of two candidate genes
Mihola, Ondřej ; Trachtulec, Zdeněk (advisor) ; Munclinger, Pavel (referee) ; Pravenec, Michal (referee)
Summaryofpublications 1. Positionalcloningof the Hybridsterility1 gene:finegenetic mappingand evaluationof twocandidategenes Hybridsteri|iýis one of the mechanismsof speciation.The Hybridsteriliý1 (HsÍí)genewasthefirstmappedmammaliangene.The geneaffectsfertiliýof male hybridsbetweencertainlaboratorystrains(suchas C57Bl/10)and Mus musculus musculusmiceby causinga breakdownof spermatogenesisat thestageof primary spermatocytes.|ntheprocessof positiona|c|oningoftheHsÍígene,Wegenerateda contigof bacterialartificialchromosomes(BACs)and subsequentlya lowcoverage sequenceof the candidateregionof the '12951/SvlmJstrain.New geneticmarkers narroweddown the HsÍíregionfrom 580 to 360 ki|obases.The productsof two genesfromthisregion,TATA-bindingprotein(Ibp)and proteasomesubunitbeta1 (Psmb1\,accumulateduringspermatogenesis.The proteinshave been described previouslyas having conservedC{erminal sequencesand species-specificN- termini.We eva|uatedthe candidacyof thesegenesfor Hsťíby a||e|icsequencing and by real-timereverse-transcriptionPCR of testicularmRNAs.The resultssuggest thatneitherthePsmÓí northe lbp genecausehybridsteri|ity.Thesing|enuc|eotide po|ymorphisms(SNPs)we havefound,was usedfor the hap|oýpeana|ysisof the HsÍíregion.
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