Dosage effects of resveratrol on thymus involution in D‐galactose‐treated mice

Author(s):  
Ting‐ting Wei ◽  
Yuan‐kang Feng ◽  
Jia‐hui Cao ◽  
Jie‐han Li ◽  
Shu‐liang Yuan ◽  
...  
Genetics ◽  
2001 ◽  
Vol 157 (4) ◽  
pp. 1711-1721
Author(s):  
Donald L Auger ◽  
Kathleen J Newton ◽  
James A Birchler

Abstract Each mitochondrion possesses a genome that encodes some of its own components. The nucleus encodes most of the mitochondrial proteins, including the polymerases and factors that regulate the expression of mitochondrial genes. Little is known about the number or location of these nuclear factors. B-A translocations were used to create dosage series for 14 different chromosome arms in maize plants with normal cytoplasm. The presence of one or more regulatory factors on a chromosome arm was indicated when variation of its dosage resulted in the alteration in the amount of a mitochondrial transcript. We used quantitative Northern analysis to assay the transcript levels of three mitochondrially encoded components of the cytochrome c oxidase complex (cox1, cox2, and cox3). Data for a nuclearly encoded component (cox5b) and for two mitochondrial genes that are unrelated to cytochrome c oxidase, ATP synthase α-subunit and 18S rRNA, were also determined. Two tissues, embryo and endosperm, were compared and most effects were found to be tissue specific. Significantly, the array of dosage effects upon mitochondrial genes was similar to what had been previously found for nuclear genes. These results support the concept that although mitochondrial genes are prokaryotic in origin, their regulation has been extensively integrated into the eukaryotic cell.


Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1851-1869 ◽  
Author(s):  
Manfred Heinlein

The pattern of aleurone variegation of maize kernels carrying Ac and bz-m2(DI) as reporter allele for Ac activity depends on the dosage of both Ac and Ds. Alterations of Ac dosage can abolish Ds excision at certain times and allow it to occur at other times. wx-m7 and wx-m9 are different Ac insertions in the Waxy gene which have different dosage effects on Ds excision. Kernels, heterozygous for the two Ac alleles and being either wx-m7/wx-m7/wx-m9 or wx-m9/wx-m9/wx-m7 exhibit characteristic patterns of predominantly late excisions; this is in strong contrast to the pattern of early excisions present on wx-m7/wx-m7/wx-m7 homozygotes. This observation supports the hypothesis that the Ac alleles express different amounts of transposase (TPase) during development and that above a certain level of TPase transposition is inhibited. Furthermore, experimental results suggest that the frequency of Ac-induced events is influenced by the dosage and composition of the transactivated Ds or Ac allele. Thus, transposition frequency seems not to be exclusively determined in trans by the amount of active TPase, but also by specific cis-acting properties of the TPase substrate.


1985 ◽  
Vol 10 (1) ◽  
pp. 1-10 ◽  
Author(s):  
André Penninks ◽  
Frieke Kuper ◽  
Ben J. Spit ◽  
Willem Seinen
Keyword(s):  

Genetics ◽  
1998 ◽  
Vol 150 (1) ◽  
pp. 251-263 ◽  
Author(s):  
Utpal Bhadra ◽  
Manika Pal Bhadra ◽  
James A Birchler

Abstract We have investigated the effect of dosage-dependent trans-acting regulators of the white eye color gene in combinations to understand their interaction properties. The consequences of the interactions will aid in an understanding of aneuploid syndromes, position-effect variegation (PEV), quantitative traits, and dosage compensation, all of which are affected by dosage-dependent modifiers. Various combinations modulate two functionally related transcripts, white and scarlet, differently. The overall trend is that multiple modifiers are noncumulative or epistatic to each other. In some combinations, developmental transitions from larvae to pupae to adults act as a switch for whether the effect is positive or negative. With position-effect variegation, similar responses were found as with gene expression. The highly multigenic nature of dosage-sensitive modulation of both gene expression and PEV suggests that dosage effects can be progressively transduced through a series of steps in a hierarchical manner.


Development ◽  
1998 ◽  
Vol 125 (18) ◽  
pp. 3543-3551 ◽  
Author(s):  
S. Bel ◽  
N. Core ◽  
M. Djabali ◽  
K. Kieboom ◽  
N. Van der Lugt ◽  
...  

In Drosophila and mouse, Polycomb group genes are involved in the maintenance of homeotic gene expression patterns throughout development. Here we report the skeletal phenotypes of compound mutants for two Polycomb group genes bmi1 and M33. We show that mice deficient for both bmi1 and M33 present stronger homeotic transformations of the axial skeleton as compared to each single Polycomb group mutant, indicating strong dosage interactions between those two genes. These skeletal transformations are accompanied with an enhanced shift of the anterior limit of expression of several Hox genes in the somitic mesoderm. Our results demonstrate that in mice the Polycomb group genes act in synergy to control the nested expression pattern of some Hox genes in somitic mesodermal tissues during development.


2000 ◽  
Vol 176 (1) ◽  
pp. 12-19 ◽  
Author(s):  
Walter J. Muir

BackgroundMedicine is rapidly becoming molecular medicine, and little escapes the grasp of modern genetics. Most disorders associated with learning disability have at least a genetic component influencing their expression; in many disorders, disturbances of genetic mechanisms play a pivotal role.AimsDynamic mutations, imprinting mechanisms and gene-dosage effects are explained with reference to genetic disorders that lead to learning disability.MethodA review of recent important studies in the genetics of learning disability.ResultsA host of new genetic connections to conditions associated with learning disability have been made.ConclusionsA basic understanding of these genetic connections is important for all learning disability psychiatrists if they are to follow the rapid changes – already beginning to influence our practice – that hold immense promise for the future.


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