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41.
Phylogenetic evidence for role-reversals of gender-associated mitochondrial DNA in Mytilus (Bivalvia: Mytilidae) 总被引:1,自引:0,他引:1
Hoeh WR; Stewart DT; Saavedra C; Sutherland BW; Zouros E 《Molecular biology and evolution》1997,14(9):959-967
Distinct gender-associated mitochondrial DNA (mtDNA) lineages (i.e.,
lineages which are transmitted either through males or through females)
have been demonstrated in two families of bivalves, the Mytilidae (marine
mussels) and the Unionidae (freshwater mussels), which have been separated
for more than 400 Myr. The mode of transmission of these M (for
male-transmitted) and F (for female-transmitted) molecules has been
referred to as doubly uniparental inheritance (DUI), in contrast to
standard maternal inheritance (SMI), which is the norm in animals. A
previous study suggested that at least three origins of DUI are required to
explain the phylogenetic pattern of M and F lineages in freshwater and
marine mussels. Here we present phylogenetic evidence based on partial
sequences of the cytochrome c oxidase subunit I gene and the 16S RNA gene
that indicates the DUI is a dynamic phenomenon. Specifically, we
demonstrate that F lineages in three species of Mytilus mussels, M. edulis,
M. trossulus, and M. californianus, have spawned separate lineages which
are now associated only with males. This process is referred to as
"masculinization" of F mtDNA. By extension, we propose that DUI may be a
primitive bivalve character and that periodic masculinization events
combined with extinction of previously existing M types effectively reset
the time of divergence between conspecific gender-associated mtDNA
lineages.
相似文献
42.
43.
Leandro M. Colli Lea Jessop Timothy A. Myers Sabrina Y. Camp Mitchell J. Machiela Jiyeon Choi Renato Cunha Olusegun Onabajo Grace C. Mills Virginia Schmid Seth A. Brodie Olivier Delattre David R. Mole Mark P. Purdue Kai Yu Kevin M. Brown Stephen J. Chanock 《American journal of human genetics》2021,108(9):1590-1610
44.
45.
Lee KM Lan Q Kricker A Purdue MP Grulich AE Vajdic CM Turner J Whitby D Kang D Chanock S Rothman N Armstrong BK 《Human genetics》2007,122(5):525-533
Dysregulation of the one-carbon metabolic pathway, which controls nucleotide synthesis and DNA methylation, may promote lymphomagenesis.
We evaluated the association between polymorphisms in one-carbon metabolism genes and risk of non-Hodgkin lymphoma (NHL) in
a population-based case-control study in Australia. Cases (n = 561) and controls (n = 506) were genotyped for 14 selected single-nucleotide polymorphisms in 10 genes (CBS, FPGS, FTHFD, MTHFR, MTHFS, MTR, SHMT1, SLC19A1, TCN1, and TYMS). We also conducted a meta-analysis of all studies of Caucasian populations investigating the association between MTHFR Ex5+79C > T (a.k.a., 677C>T) and NHL risk. A global test of 13 genotypes was statistically significant for diffuse large B-cell lymphoma (DLBCL; P = 0.008), but not for follicular lymphoma (FL; P = 0.27) or all NHL (P = 0.17). The T allele at MTHFR Ex5+79 was marginally significantly associated with all NHL (OR = 1.25, 95% CI = 0.98–1.59) and DLBCL (1.36, 0.96–1.93). The T allele at TYMS
Ex8+157 was associated with a reduced risk of FL (0.64, 0.46–0.91). An elevated risk of NHL was also observed among carriers of the
G allele at FTHFD
Ex21+31 (all NHL, 1.31, 1.02–1.69; DLBCL, 1.50, 1.05–2.14). A meta-analysis of 11 studies conducted in Caucasian populations of European
origin (4,121 cases and 5,358 controls) supported an association between the MTHFR Ex5+79
T allele and increased NHL risk (additive model, P = 0.01). In conclusion, the results of this study suggest that genetic polymorphisms of one-carbon metabolism genes such as
MTHFR and TYMS may influence susceptibility to NHL.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
46.
47.
Tianbao Yang Gul Shad Ali Lihua Yang Liqun Du ASN Reddy BW Poovaiah 《Plant signaling & behavior》2010,5(8):991-994
Recently we reported that CRLK1, a novel calcium/calmodulin-regulated receptor-like kinase plays an important role in regulating plant cold tolerance. Calcium/calmodulin binds to CRLK1 and upregulates its activity. Gene knockout and complementation studies revealed that CRLK1 is a positive regulator of plant response to chilling and freezing temperatures. Here we show that MEKK1, a member of MAP kinase kinase kinase family, interacts with CRLK1 both in vitro and in planta. The cold triggered MAP kinase activation in wild-type plants was abolished in crlk1 knockout mutants. Similarly, the cold induced expression levels of genes involved in MAP kinase signaling are also altered in crlk1 mutants. These results suggest that calcium/calmodulinregulated CRLK1 modulates cold acclimation through MAP kinase cascade in plants.Key words: calcium, calmodulin, cold stress, MAPK, Arabidopsis, protein phosphorylationCalcium, a universal second messenger in eukaryotic cells, mediates changes in external and internal signals leading to the physiological responses.1–4 Calcium/calmodulin (Ca2+/CaM)-dependent protein kinases (CaMKs) are very important players in calcium/calmodulin mediated signaling in mammalian cells.5 In plants, Ca2+/CaM-dependent protein phosphorylation was observed more than 25 years ago.6 Several calmodulin-regulated protein kinases have been identified and characterized.7,8 For example, plants have a unique chimeric Ca2+/CaM-dependent protein kinase (CCaMK), which exhibits Ca2+-dependent autophosphorylation and Ca2+/CaM-dependent substrate phosphorylation.9 CCaMK is required for bacterial and fungal symbioses in plants.10–12 Recently, we characterized a novel plant-specific calcium/CaM-regulated receptor-like kinase, CRLK1.13 Ca2+/CaM binds to CRLK1 and stimulates its kinase activity. Functional studies with CRLK1 indicate that CRLK1 acts as a positive regulator in plant response to chilling and freezing temperatures. To further define the CRLK1-mediated signal pathway, we isolated CRLK1 interacting proteins by co-immunoprecipitation using an anti-CRLK1 antibody. Since cold increases the amount of CRLK1 protein, wildtype plants (WT) were treated at 4°C for 1 hr before co-immunoprecipitation. The resulting CRLK1 immunocomplex was separated by SDS-PAGE. We observed several bands of different sizes only in the wild-type but not in the crlk1 knockout mutant plants (Fig. 1A). Furthermore, the intensity of these bands increased upon cold treatment, suggesting that they are the putative partners or associated proteins of the CRLK1 immunocomplex.Open in a separate windowFigure 1CRLK1 Interacts with MEKK1. (A) One-dimension SDS-PAGE of anti-CRLK1 immunocomplexes from 3-week-old WT or crlk1 plants with or without cold treatment. One mg of total protein was used for immunoprecipitation. (B) A list of putative CRLK1-interacting proteins determined by MALDI-TOF-MS analysis. (C) CRLK1 interacts with MEKK1 as shown by GST pull-down assay. (D) BiFC analysis show that CR LK associates with MEKK1 in vivo. Upper row shows that CRLK and MEKK1 associate both on cell membrane and in endosomes. The middle and last rows are controls. Bar = 10 µm.To determine the identities of these proteins, mass spectrometric analysis was performed with the total immunocomplex.14 In addition to CRLK1, there were 12 other proteins which matched the Arabidopsis database. Several of them appeared in the pull-down complex from WT, but not from crlk1 mutants. These putative interacting proteins included MEKK1, another unknown protein kinase, a type 2C phosphatase and CaM (Fig. 1B). MEKK1 is one of the 60 putative MAPKKKs in the Arabidopsis genome, and sits on the top of mitogen-activated protein kinase (MAPK) cascade. The MAPK signaling consists of a cascade of three consecutively acting protein kinases, a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK) and a MAP kinase (MAPK). Plants possess multiple MAPKKKs, MAPKKs and MAPKs, which respond to different upstream signals and activate distinct downstream pathways.15–17 The specific MAPK module responding to lower temperature has been determined in Arabidopsis.18,19 MEKK1, a member of MAPKKKs, specifically interacts and phosphorylates MKK2 and regulates COR genes expression in response to cold stress.19 MEKK1 has been shown to play a role in mediating reactive oxygen species homeostasis.20,21 Therefore we selected MEKK1 from the putative CRLK1 partners for further studies. 相似文献
48.
Kiwoong Nam Carina Mugal Benoit Nabholz Holger Schielzeth Jochen BW Wolf Niclas Backström Axel Künstner Christopher N Balakrishnan Andreas Heger Chris P Ponting David F Clayton Hans Ellegren 《Genome biology》2010,11(6):1-17
Background
Obtaining a draft genome sequence of the zebra finch (Taeniopygia guttata), the second bird genome to be sequenced, provides the necessary resource for whole-genome comparative analysis of gene sequence evolution in a non-mammalian vertebrate lineage. To analyze basic molecular evolutionary processes during avian evolution, and to contrast these with the situation in mammals, we aligned the protein-coding sequences of 8,384 1:1 orthologs of chicken, zebra finch, a lizard and three mammalian species.Results
We found clear differences in the substitution rate at fourfold degenerate sites, being lowest in the ancestral bird lineage, intermediate in the chicken lineage and highest in the zebra finch lineage, possibly reflecting differences in generation time. We identified positively selected and/or rapidly evolving genes in avian lineages and found an over-representation of several functional classes, including anion transporter activity, calcium ion binding, cell adhesion and microtubule cytoskeleton.Conclusions
Focusing specifically on genes of neurological interest and genes differentially expressed in the unique vocal control nuclei of the songbird brain, we find a number of positively selected genes, including synaptic receptors. We found no evidence that selection for beneficial alleles is more efficient in regions of high recombination; in fact, there was a weak yet significant negative correlation between ω and recombination rate, which is in the direction predicted by the Hill-Robertson effect if slightly deleterious mutations contribute to protein evolution. These findings set the stage for studies of functional genetics of avian genes. 相似文献49.
50.
Peter Purdue 《Bulletin of mathematical biology》1974,36(3):305-309
The stochastic model of a compartment developed by Thakur, Rescigno and Schafer is discussed without using generating functions. The behavior of the mean and variance of the number of particles present as a function of time is also discussed. We also allow both the input and output to be time dependent. 相似文献