The Experts below are selected from a list of 18 Experts worldwide ranked by ideXlab platform
Outi Savolainen - One of the best experts on this subject based on the ideXlab platform.
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Nuclear-Cytoplasmic Interactions reduce male fertility in hybrids of Arabidopsis lyrata subspecies.
Evolution; international journal of organic evolution, 2011Co-Authors: Johanna Leppälä, Outi SavolainenAbstract:We examined the level of postzygotic reproductive isolation in F(1) and F(2) hybrids of reciprocal crosses between the Arabidopsis lyrata subspecies lyrata (North American) and petraea (European). Our main results are: first, the percentage of fertile pollen was significantly reduced in the F(1) and F(2) compared to the parental populations. Second, mean pollen fertility differed markedly between reciprocal crosses: 84% in the F(2) with ssp. lyrata cytoplasm and 61% in the F(2) with ssp. petraea cytoplasm. Third, 17% of the F(2) with ssp. petraea cytoplasm showed male sterility (produced less than 30 pollen grains in our subsample). The hybrids were female fertile. We used QTL mapping to find the genomic regions that determine pollen fertility and that restore cytoplasmic male sterility (CMS). In the F(2) with ssp. lyrata cytoplasm, an epistatic pair of QTLs was detected. In the reciprocal F(2) progeny, four QTLs demonstrated within-population polymorphism for hybrid male sterility. In addition, in the F(2) with ssp. petraea cytoplasm, there was a strong male fertility restorer locus on chromosome 2 where a cluster of CMS restorer gene-related PPR genes have been found in A. lyrata. Our results underline the importance of cytonuclear Interactions in understanding genetics of the early stages of speciation.
Douglas C Wallace - One of the best experts on this subject based on the ideXlab platform.
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diseases of the mitochondrial dna
Annual Review of Biochemistry, 1992Co-Authors: Douglas C WallaceAbstract:INTRODUCTION . . _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 175 THE HUMAN MITOCHONDRIAL DNA AND OXIDATIVE PHOSPHORYLATION 1176 Mitochondrial Biogenesis ... 1 176 Mitochondrial OXPHOS Complexes and their Synthesis 1 178 Developmental Regulation of Nuclear OXPHOS Genes 1179 Mitochondrial DNA Genetics 1 1 8 1 MITOCHONDRIAL DNA MUTATIONS AND DISEASE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 183 Missense Mutations 1184 Biogenesis Mutations 1 1 88 Insertion-Deletion Mutations . 1 192 Copy Number Mutations 1 195 DEFECTS IN Nuclear-Cytoplasmic Interactions . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . 1 195 THE PROGRESSION OF OXPHOS DISEASES AND AGING 1 196 EVIDENCE FOR OXPHOS DEFECTS IN COMMON DEGENERATIVE DISEASES . . ... . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . 1201 METABOLIC AND GENETIC THERAPY OF OXPHOS DEFECTS 1206
Francoise Budar - One of the best experts on this subject based on the ideXlab platform.
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identification of the fertility restoration locus rfo in radish as a member of the pentatricopeptide repeat protein family
EMBO Reports, 2003Co-Authors: Sophie Desloire, Hassen Gherbi, Wassila Laloui, Sylvie Marhadour, Vanessa Clouet, Laurence Cattolico, Cyril Falentin, Sandra Giancola, Michel Renard, Francoise BudarAbstract:Ogura cytoplasmic male sterility (CMS) in radish (Raphanus sativus) is caused by an aberrant mitochondrial gene, Orf138, that prevents the production of functional pollen without affecting female fertility. Rfo, a nuclear gene that restores male fertility, alters the expression of Orf138 at the post-transcriptional level. The Ogura CMS/Rfo two-component system is a useful model for investigating nuclear–cytoplasmic Interactions, as well as the physiological basis of fertility restoration. Using a combination of positional cloning and microsynteny analysis of Arabidopsis thaliana and radish, we genetically and physically delimited the Rfo locus to a 15-kb DNA segment. Analysis of this segment shows that Rfo is a member of the pentatricopeptide repeat (PPR) family. In Arabidopsis, this family contains more than 450 members of unknown function, although most of them are predicted to be targeted to mitochondria and chloroplasts and are thought to have roles in organellar gene expression.
Ian Wilmut - One of the best experts on this subject based on the ideXlab platform.
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nuclear cytoplasmic Interactions during the first cell cycle of nuclear transfer reconstructed bovine embryos implications for deoxyribonucleic acid replication and development
Biology of Reproduction, 1993Co-Authors: Keith H S Campbell, W A Ritchie, Ian WilmutAbstract:The present study investigated the decay of maturation-promoting factor (MPF) activity in electrically activated in vitro-matured bovine oocytes and examined the influence of the cell cycle stage of both the donor nucleus and the recipient cytoplasm upon the morphology and DNA synthesis potential of the donor nucleus in reconstructed embryos. The decay of MPF activity was studied both biochemically in electrically activated in vitro-matured oocytes and by morphological examination of nuclear structure in reconstructed bovine embryos. As measured by H1 kinase activity in groups of 10 oocytes, the level of MPF declined rapidly to 30 +/- 4% (of the maximum level in unactivated control oocytes) at 60 min and reached a basal level of 20 +/- 6% at 120 min. This level of activity was then maintained until at least 9 h postactivation. In contrast, when MPF activity was assayed by morphological examination of nuclei in individual reconstructed embryos, the decline in activity occurred over a period of 9 h postactivation. DNA synthesis of nuclei arrested at the G1/S border and in G2 phases of the cell cycle was examined in embryos reconstructed at the time of oocyte activation, i.e., when MPF levels were maximal, and by fusion 10 h postactivation, when no MPF activity could be detected. All nuclei transferred at the time of oocyte activation underwent nuclear envelope breakdown (NEBD) and subsequent DNA synthesis. However, when nuclei were transferred 10 h after activation, no NEBD was observed in any nuclei. Nuclei arrested at the G1/S border or nuclei in S phase when transferred in the absence of NEBD underwent DNA synthesis, while no DNA synthesis was observed in G2 nuclei transferred into this cytoplasmic environment. The results presented show that all nuclei, regardless of cell cycle stage, undergo DNA replication when transplanted into metaphase II (MeII) cytoplasts in which MPF activity is high. From these observations we would suggest that one factor that may contribute to the present low frequency of development of bovine nuclear transfer embryos is the ploidy of the reconstructed embryo after the first cell cycle. In order to maintain correct ploidy of the reconstructed embryo, only G1 nuclei should be transferred at the time of activation, when MPF levels are high. In contrast, when the integrity of the nuclear membrane is maintained by transfer at 10 h postactivation, when MPF activity is absent, the rereplication of G2 nuclei is prevented and correct ploidy of the reconstructed embryo may be maintained.
Johanna Leppälä - One of the best experts on this subject based on the ideXlab platform.
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Nuclear-Cytoplasmic Interactions reduce male fertility in hybrids of Arabidopsis lyrata subspecies.
Evolution; international journal of organic evolution, 2011Co-Authors: Johanna Leppälä, Outi SavolainenAbstract:We examined the level of postzygotic reproductive isolation in F(1) and F(2) hybrids of reciprocal crosses between the Arabidopsis lyrata subspecies lyrata (North American) and petraea (European). Our main results are: first, the percentage of fertile pollen was significantly reduced in the F(1) and F(2) compared to the parental populations. Second, mean pollen fertility differed markedly between reciprocal crosses: 84% in the F(2) with ssp. lyrata cytoplasm and 61% in the F(2) with ssp. petraea cytoplasm. Third, 17% of the F(2) with ssp. petraea cytoplasm showed male sterility (produced less than 30 pollen grains in our subsample). The hybrids were female fertile. We used QTL mapping to find the genomic regions that determine pollen fertility and that restore cytoplasmic male sterility (CMS). In the F(2) with ssp. lyrata cytoplasm, an epistatic pair of QTLs was detected. In the reciprocal F(2) progeny, four QTLs demonstrated within-population polymorphism for hybrid male sterility. In addition, in the F(2) with ssp. petraea cytoplasm, there was a strong male fertility restorer locus on chromosome 2 where a cluster of CMS restorer gene-related PPR genes have been found in A. lyrata. Our results underline the importance of cytonuclear Interactions in understanding genetics of the early stages of speciation.
