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Genetic interactions of the Prdm9 gene
Šebestová, Lenka ; Trachtulec, Zdeněk (advisor) ; Král, Jiří (referee)
The Prdm9 gene (PR domain containing 9, Meisetz, Hybrid sterility 1) encodes enzyme that trimethylates histone 3 on lysines 4 and 36. These methylation marks determine the positions of DNA double-strand breaks that are repaired by meiotic homologous recombination. In this study, we assayed genetic interactions of Prdm9 with two genes important for spermatogenesis - Mili (Piwil2) involved in piRNA biogenesis and Mybl1 encoding transcription factor that regulates many genes important for prophase I, including piRNA precursors. We crossed laboratory mice carrying mutation in Prdm9 with heterozygotes for mutation in Mybl1 or Mili, and created compound heterozygotes and, in case of Mybl1, also double homozygotes. We assessed body weight and male fertility parameters (weight of testes, sperm count, malformed sperm, percentage of tubules containing spermatocytes and of abnormal nuclei of pachytene spermatocytes) of these mice and compared them to controls. We also investigated the effect of Mybl1 and Mili mutations on fecundity of F1 intersubspecific hybrids. Our results revealed possible interactions of Prdm9 and Mybl1 in the laboratory mouse. Decreased gene dosage of Mybl1 reduced fertility of intersubspecific F1 hybrids. Interaction between Prdm9 and Mili in both laboratory mouse and F1 hybrids remain...
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The role of methylation of histone 3 on lysine 4 (H3K4) during mouse spermatogenesis
Blumenstein, Jan ; Trachtulec, Zdeněk (advisor) ; Král, Jiří (referee)
Epige eti ké odifika e hro ati u hrají z ač ou roli v regula i přístup osti DNA. odifika í je etyla e histo ů. V H a lysi u ěhe sper atoge eze yši do á í a to zej é a ve Běhe eioti ké profáze I do hází k hro ozo ů, a k eioti ké reko i a i. Tyto pro esy jsou kriti ký ode tvor y pohlav í h u ěk a jeji h selhá í vede k eioti ké zástavě a tí páde k poruše tvor y haploid í h u ěk. Histo ová etyltra sferáza PRDM9 hraje klíčovou roli v eioti ké reko i a e, e oť je zodpověd á za urče í progra ova ý h dvouřetěz ový h zlo ů v íste h zva ý h hotspoty. Ni é ě ge je důležitý i ve spe ia i, a to řed i tví fe o é u hy rid í sterility. Další i protei y, které se podílí a etyla i histo u H a lysi u ěhe sper atoge eze, jsou MLL KMT D , MLL KMT E a yší h varlate h ovše az ačují, že regula i této odifika e hro ati u podílí ví e ge ů. Avšak ejsou z á é ko krét í fu k e, které ají tyto z ývají í ge y ěhe vývoje sa čí h pohlav í h u ěk. Další zkou á í tě hto ge ů ohou ýt užiteč á pro o jas ě í částeč é e o úpl é eplod os Klíčová slova: eioti ká reko i a e, dvouřetěz ové zlo y, hy rid í sterilita, sper atoge eze, etyla e histo ů
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The role of cohesin genes in the meiosis of male house mouse
Šebestová, Lenka ; Trachtulec, Zdeněk (advisor) ; Král, Jiří (referee)
Cohesin genes play an important role in cell division. They ensure proper chromosome segregation during mitosis and meiosis. This study is focused on the role of cohesin genes during meiosis in male house mouse (Mus musculus). At first, this study introduces key processes of mammalian meiosis. Next, the structure of cohesin complex is described; it consists of a heterodimer SMC proteins - SMC3 and SMC1α or SMC1β, which are enclosed to the ring by cleavable subunit RAD21, RAD21L or REC8. Fourth subunit - a STAG protein (STAG1, STAG2 or STAG3) associates with the cleavable subunit. Meiotic function of specific cohesin proteins (SMC1β, RAD21L, REC8 and STAG3) as deduced from the phenotypes of the deficiencies of their genes in male mouse is depicted. All these four genes are necessary for many processes during meiosis, - e.q. sister chromatid cohesion maintenance, synapsis and recombination. STAG3, SMC1β, and REC8 are necessary for centromeric cohesion. STAG3 and RAD21L are important for the assembly of the remaining cohesin subunits. The most important phenotype of deficiency of all four genes is the complete meiotic arrest in male prophase I. Therefore, cohesin research is important for the investigation of the causes of sterility in mammals. key words: cohesin, meiosis, spermatogenesis, mouse,...
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Maping of genes modifying the subspecies-specific roles of the meiotic gene Prdm9
Škaloudová, Eliška ; Trachtulec, Zdeněk (advisor) ; Schierová, Michaela (referee)
The PRDM9 (PR domain containing 9) protein is an epigenetic factor that trimethylates lysine 4 of histone H3 and thereby determines the future meiotic double-strand breaks - sites important for proper segregation of homologous chromosomes. Males of the Mus musculus domesticus (Mmd) origin with homozygous deletion in Prdm9 (Prdm9-/- ) are sterile with a complete arrest in meiotic prophase I, in contrast to the same mutant males of the M. m. musculus (Mmm) subspecies. The aim of this diploma thesis was to identify the genomic loci responsible for the phenotypic difference of these Prdm9-/- males. The major research tool was a population of 182 Mmm x Mmd Prdm9-/- males. The mapping method of quantitative trait loci (QTLs) was based on relating the genotypes of single-nucleotide and microsatellite polymorphisms to the observed phenotypes. At least two QTLs on Chr X were identified. The Mmm alleles of these QTLs reduced fertility of Prdm9-/- males. Both QTLs were confirmed and narrowed down using two types of subconsomic strains. It was not possible to confirm other QTLs, particularly on autosomes. This QTL mapping is the first step towards the identification of genes that modify the resulting phenotype of Prdm9-/- animals. This identification should help designing studies of human infertility that...
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Genes of early meiotic prophase I of spermatogenesis in house mouse
Škaloudová, Eliška ; Trachtulec, Zdeněk (advisor) ; Forman, Martin (referee)
Meiosis is an essential cellular process that is necessary for gamete formation in all sexually reproducing organisms. This work is focused on the description of the genes of early stages of meiotic division in males of a mammalian model, the house mouse. The first part summarizes meiosis focusing on prophase I, which is longer than prophase II. Prophase I is divided into five stages, namely leptotene, zygotene, pachytene, diplotene, and diakinesis. Mouse spermatogenesis and its differences from oogenesis are also briefly described. The second part provides a list of genes encoding proteins required for initiation of meiotic division, pairing and synapses of chromosomes, and initiation of the catalysis of double-strand breaks. Double-strand breaks are repaired by homologous recombination, which may result in so-called crossing-over, the major source of genetic variability. The work deals with the early stage of homologous recombination and components required for this process. Localization of meiotic double-strand breaks in the genome is not random and is under the control of the Prdm9 gene, which seems to take multiple roles, such as the formation of new subspecies of the house mouse. Knowledge of the genes controlling the early stages of meiotic division is a prerequisite to understanding some of...
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Evolution and expression of the Odorant Binding Proteins in selected species of mice
Vinkler, David ; Stopka, Pavel (advisor) ; Trachtulec, Zdeněk (referee)
Odorant-binding proteins (OBPs) are small soluble proteins expressed at high levels in the proximity of olfactory receptors. OBPs act as solubilizers and carriers of the lipophilic odorants in the aqueous mucus of mammals and other vertebrates. OBPs have now been studied nearly thirty years, but in comparison to the wealth of data available on their structural chemistry and molecular biology, our knowledge about gene expression and function of these proteins is still insufficient. This work provides new insights into the tissue specificity of OBP and presents several new sequences of genes governing these proteins in selected species of mice.
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Establishment and phenotyping of three mouse congenic strains.
Flachs, Petr ; Trachtulec, Zdeněk (advisor) ; Vopálenský, Václav (referee)
Mouse congenic strains are widely used as an important genetic tool for various purposes of research. Congenic strains are special inbred strains in which part of the genome of one mouse is transferred to another by backcrossing the donor mouse to the recipient strain with appropriate selection. The classical ten-generation breeding protocol is commonly utilized and adapted for different experimental needs. Our department is focused on the study of hybrid sterility between two related mouse strains M. m. musculus and M. m. domesticus. The first aim of this work was the utilization of congenics to stabilize three transgenic lines, which previously helped to identify first mammalian hybrid sterility gene Hst1 as Prdm9 (Mihola et al, 2009). Bacterial artificial chromosomes (BACs) present in transgenes encompassed several genes including Prdm9. The second goal was to look for some new phenotypes of our congenic strains, which may be causally associated with genes encoded by the BACs, as well as an additional research on the hybrid sterility phenomena. We established three new congenic strains on C57BL/6J (B6) background and found significant differences between transgenics versus their littermate controls in weights of testis, gonadal fat, body, liver, and heart. Powered by TCPDF (www.tcpdf.org)
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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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