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排序方式: 共有239条查询结果,搜索用时 15 毫秒
1.
About the specificity of photoinduced affinity labeling of Escherichia coli ribosomes by dihydrorosaramicin, a macrolide related to erythromycin 总被引:1,自引:0,他引:1
Photoactivation of the [3H]dihydrorosaramicin chromophore at a wavelength above 300 nm allows the covalent attachment of the macrolide antibiotic to the bacterial ribosome. Bidimensional electrophoresis shows that the radioactivity is mainly associated with proteins L1, L5, L6, L15, L18, L19, S1, S3, S4, S5 and S9. When photoincorporation of the drug is conducted in the presence of puromycin as effector of [3H]dihydrorosaramicin-binding sites, a decrease in the labeling of most proteins is observed, except for L18 and L19, which are radiolabeled to a larger extent. These results allow us to speculate that L18 and L19 belong to the high-affinity binding site of rosaramicin antibiotic. 相似文献
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4.
Assignment of the human gamma-glutamyl transferase gene to the long arm of chromosome 22 总被引:3,自引:0,他引:3
F. Bulle M. G. Mattei S. Siegrist A. Pawlak E. Passage M. N. Chobert Y. Laperche G. Guellaën 《Human genetics》1987,76(3):283-286
Summary We have determined the chromosomal location of the human gene for gamma-glutamyltransferase (GGT). This study was done by in situ hybridization of human metaphase spreads with a rat cDNA probe specific for this enzyme and constructed from two clones previously characterized in our laboratory. The final construct had a 1.6-kb-long insert covering 92% of the coding sequence for GGT. The new insert was also freed of any GC tails introduced for the cDNA cloning, because we observed that these sequences were responsible for a high background. Using this probe for the analysis of 136 human metaphase spreads, we observed a strong specific signal on chromosome 22 at the interface of q111-112 and a minor peak in q131. Thus GGT might represent a new marker for the study of certain diseases which have chromosomal abnormalities at these loci. 相似文献
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6.
Regulation of mouse mammary-gland gamma-glutamyltranspeptidase mRNA during pregnancy, lactation and weaning.
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S Siegrist Y Laperche M N Chobert F Bulle H L Nakhasi G Guella?n 《The Biochemical journal》1990,267(3):621-624
The level of gamma-glutamyltranspeptidase (GGT) activity and of its mRNA were determined in the mouse mammary gland during pregnancy, lactation and weaning. The GGT activity, which is very low in the virgin-mouse mammary gland (5 munits/mg of protein), increases progressively during pregnancy (3-fold), reaches its maximum at the onset of lactation (8-fold) and returns rapidly to basal level at weaning. Although no GGT-specific mRNA is detected in the virgin-mouse mammary gland, a single faint band of 2.2 kb in size is found during pregnancy. During lactation, an additional mRNA of 2.4 kb in size appears, and the level of both mRNAs is higher. This high level of mRNA persists during weaning as well. Southern-blot analysis of mouse mammary-gland DNA provides convincing evidence that there is only one gene which codes for the two mRNAs. The present study provides the first evidence for a physiological regulation of the two GGT mRNAs in the same tissue. 相似文献
7.
gamma-Glutamyl transpeptidase: a single copy gene in the rat and a multigene family in the human genome 总被引:5,自引:0,他引:5
A Pawlak O Lahuna F Bulle A Suzuki N Ferry S Siegrist N Chikhi M N Chobert G Guellaen Y Laperche 《The Journal of biological chemistry》1988,263(20):9913-9916
gamma-Glutamyl transpeptidase (GGT) genomic sequences were isolated from rat and human libraries using a rat GGT cDNA as a cross-species hybridization probe. Characterization of the human GGT clones by restriction mapping clearly establishes that at least four different GGT genes or pseudogenes are present in the human genome. All the rat genomic clones cover a 12.5-kilobase sequence and exhibit a unique restriction pattern. A precise quantitation of the rat GGT gene copy number by Southern blot analysis demonstrates that this sequence is present as a single copy/rat haploid genome. Therefore, the GGT gene organization is different between rat and human species; this raises the possibility of different regulatory mechanisms in the two species. 相似文献
8.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
9.
A major difference between the divergence patterns within the lines-1 families in mice and voles 总被引:3,自引:0,他引:3
Vanlerberghe F; Bonhomme F; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1993,10(4):719-731
L1 retroposons are represented in mice by subfamilies of interspersed
sequences of varied abundance. Previous analyses have indicated that
subfamilies are generated by duplicative transposition of a small number of
members of the L1 family, the progeny of which then become a major
component of the murine L1 population, and are not due to any active
processes generating homology within preexisting groups of elements in a
particular species. In mice, more than a third of the L1 elements belong to
a clade that became active approximately 5 Mya and whose elements are >
or = 95% identical. We have collected sequence information from 13 L1
elements isolated from two species of voles (Rodentia: Microtinae: Microtus
and Arvicola) and have found that divergence within the vole L1 population
is quite different from that in mice, in that there is no abundant
subfamily of homologous elements. Individual L1 elements from voles are
very divergent from one another and belong to a clade that began a period
of elevated duplicative transposition approximately 13 Mya. Sequence
analyses of portions of these divergent L1 elements (approximately 250 bp
each) gave no evidence for concerted evolution having acted on the vole L1
elements since the split of the two vole lineages approximately 3.5 Mya;
that is, the observed interspecific divergence (6.7%-24.7%) is not larger
than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses
showed no clustering into Arvicola and Microtus clades.
相似文献
10.
Molecular phylogeny and divergence times of drosophilid species 总被引:32,自引:15,他引:17
The phylogenetic relationships and divergence times of 39 drosophilid
species were studied by using the coding region of the Adh gene. Four
genera--Scaptodrosophila, Zaprionus, Drosophila, and Scaptomyza (from
Hawaii)--and three Drosophila subgenera--Drosophila, Engiscaptomyza, and
Sophophora--were included. After conducting statistical analyses of the
nucleotide sequences of the Adh, Adhr (Adh-related gene), and nuclear rRNA
genes and a 905-bp segment of mitochondrial DNA, we used Scaptodrosophila
as the outgroup. The phylogenetic tree obtained showed that the first major
division of drosophilid species occurs between subgenus Sophophora (genus
Drosophila) and the group including subgenera Drosophila and Engiscaptomyza
plus the genera Zaprionus and Scaptomyza. Subgenus Sophophora is then
divided into D. willistoni and the clade of D. obscura and D. melanogaster
species groups. In the other major drosophilid group, Zaprionus first
separates from the other species, and then D. immigrans leaves the
remaining group of species. This remaining group then splits into the D.
repleta group and the Hawaiian drosophilid cluster (Hawaiian Drosophila,
Engiscaptomyza, and Scaptomyza). Engiscaptomyza and Scaptomyza are tightly
clustered. Each of the D. repleta, D. obscura, and D. melanogaster groups
is monophyletic. The splitting of subgenera Drosophila and Sophophora
apparently occurred about 40 Mya, whereas the D. repleta group and the
Hawaiian drosophilid cluster separated about 32 Mya. By contrast, the
splitting of Engiscaptomyza and Scaptomyza occurred only about 11 Mya,
suggesting that Scaptomyza experienced a rapid morphological evolution. The
D. obscura and D. melanogaster groups apparently diverged about 25 Mya.
Many of the D. repleta group species studied here have two functional Adh
genes (Adh-1 and Adh-2), and these duplicated genes can be explained by two
duplication events.
相似文献