共查询到20条相似文献,搜索用时 31 毫秒
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L. S. Melnikova I. V. Krivega P. G. Georgiev A. K. Golovnin 《Russian Journal of Genetics》2007,43(12):1415-1419
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Recent data suggest that insulators organize chromatin architecture in the nucleus. The best characterized Drosophila insulator, found in the gypsy retrotransposon, contains 12 binding sites for the Su(Hw) protein. Enhancer blocking, along with Su(Hw), requires BTB/POZ domain proteins, Mod(mdg4)-67.2 and CP190. Inactivation of Mod(mdg4)-67.2 leads to a direct repression of the yellow gene promoter by the gypsy insulator. Here, we have shown that such repression is regulated by the level of the EAST protein, which is an essential component of the interchromatin compartment. Deletion of the EAST C-terminal domain suppresses Su(Hw)-mediated repression. Partial inactivation of EAST by mutations in the east gene suppresses the enhancer-blocking activity of the gypsy insulator. The binding of insulator proteins to chromatin is highly sensitive to the level of EAST expression. These results suggest that EAST, one of the main components of the interchromatin compartment, can regulate the activity of chromatin insulators. 相似文献
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The results obtained at our laboratory during several last years suggest that a specific telomeric chromatin is formed at the terminal regions of Drosophila melanogaster DNA of 4–5 kb in length. In this work, we have studied how the telomeric chromatin influences the Polycomb-dependent repression. Many Polycomb proteins are involved in the formation of subtelomeric chromatin and inhibit the expression of a transgene inserted into it. However, the question on a positive or negative effect of telomeric chromatin on the assembly of subtelomeric protein complexes is yet open. Using a model system, in which a P element inserted upstream of the yellow gene promoter and located at the end of a terminally deleted chromosome can serve as a binding site for Pc-G proteins in the presence of ph p1 mutant allele, we have shown that a specific structure of the telomeric chromatin negatively influences the formation of Polycomb-dependent repression complex. These results suggest an antagonism between the telomeric and subtelomeric (Pc-G-dependent) chromatins. 相似文献
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Gaurav Kumar Singh Sharanbasappa Shrimant Karade Rajeev Ranjan Nafees Ahamad Shakil Ahmed 《Molecular biology reports》2017,44(1):89-96
The mitotic arrest deficiency 2 (Mad2) protein is an essential component of the spindle assembly checkpoint that interacts with Cdc20/Slp1 and inhibit its ability to activate anaphase promoting complex/cyclosome (APC/C). In bladder cancer cell line the C-terminal residue of the mad2 gene has been found to be deleted. In this study we tried to understand the role of the C-terminal region of mad2 on the spindle checkpoint function. To envisage the role of C-terminal region of Mad2, we truncated 25 residues of Mad2 C-terminal region in fission yeast S.pombe and characterized its effect on spindle assembly checkpoint function. The cells containing C-terminal truncation of Mad2 exhibit sensitivity towards microtubule destabilizing agent suggesting perturbation of spindle assembly checkpoint. Further, the C-terminal truncation of Mad2 exhibit reduced viability in the nda3-KM311 mutant background at non-permissive temperature. Truncation in mad2 gene also affects its foci forming ability at unattached kinetochore suggesting that the mad2-?CT mutant is unable to maintain spindle checkpoint activation. However, in response to the defective microtubule, only brief delay of mitotic progression was observed in Mad2 C-terminal truncation mutant. In addition we have shown that the deletion of two β strands of Mad2 protein abolishes its ability to interact with APC activator protein Slp1/Cdc20. We purpose that the truncation of two β strands (β7 and β8) of Mad2 destabilize the safety belt and affect the Cdc20-Mad2 interaction leading to defects in the spindle checkpoint activation. 相似文献
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We have studied the molecular characteristics of the yellow locus (y; 1–0.0), which determines the body color of phenotypically wild-type and mutant alleles isolated in different years from geographically distant populations of Drosophila melanogaster. According to the Southern blot, data restriction maps of the yellow locus of all examined strains differ from one another, as well as from Oregon stock. FISH analysis shows that, in the neighborhood of the yellow locus in the X chromosome, neither P nor hobo elements are found in y1–775 stock, while only hobo is found in these region in y1–859 and y1–866 stocks, only the P element is found in y+sn849 stock, and both elements are found in y1–719 stock. Thus, all yellow mutants studied are of independent origin. Locus yellow located on the end of X chromosome (region 1A5–8 on the cytologic map) carries significantly more transposon than retrotransposon induced mutations compared to the white locus (region 3C2). It is possible that, at the ends of Drosophila melanogaster chromosomes, transposons are more active than retrotransposons. 相似文献
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Raghavendra P. Savada Jocelyn A. Ozga Charitha P. A. Jayasinghege Kosala D. Waduthanthri Dennis M. Reinecke 《Plant molecular biology》2017,93(3):313-326
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We identified and cloned the two precursors of miR158 and its target gene in Brassica campestris ssp. chinensis, which both had high relative expression in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility, which was caused by the degradation of pollen contents from the binucleate microspore stage. These results first suggest the role of miR158 in pollen development of Brassica campestris ssp. chinensis.Abstract
MicroRNAs (miRNAs) play crucial roles in many important growth and development processes both in plants and animals by regulating the expression of their target genes via mRNA cleavage or translational repression. In this study, miR158, a Brassicaceae specific miRNA, was functionally characterized with regard to its role in pollen development of non-heading Chinese cabbage (Brassica campestris ssp. chinensis). Two family members of miR158 in B. campestris, namely bra-miR158a1 and bra-miR158a2, and their target gene bra027656, which encodes a pentatricopeptide repeat (PPR) containing protein, were identified. Then, qRT-PCR analysis and GUS-reporter system revealed that both bra-miR158 and its target gene had relatively high expression levels in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility and pollen germination ratio, and the degradation of pollen contents from the binucleate microspore stage was also found in those deformed pollen grains, which led to pollen shrinking and collapse in later pollen development stage. These results first shed light on the importance of miR158 in pollen development of Brassica campestris ssp. chinensis.15.
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The evidence presented herein strongly suggests that lethality of homozygousyellow embryos is expressed at the primary implantation stage of embryonic development. Furthermore the expression of the mutant gene appears to be restricted to a specific cell type—the trophoblast giant cell. The stage of developmental arrest is determined by the degree of differentiation and implantation of these cells. Receptivity of the endometrium to giant cell attachment is also an important contributing factor to lethality of homozygousA y embryos. 相似文献
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T. H. Samigullin M. D. Logacheva E. I. Terenteva G. V. Degtjareva C. M. Vallejo-Roman 《Biochemistry. Biokhimii?a》2016,81(9):981-985
This work reports the complete plastid (pt) DNA sequence of Seseli montanum L. of the Apiaceae family, determined using next-generation sequencing technology. The complete genome sequence has been deposited in GenBank with accession No. KM035851. The S. montanum plastome is 147,823 bp in length. The plastid genome has a typical structure for angiosperms and contains a large single-copy region (LSC) of 92,620 bp and a small single-copy region (SSC) of 17,481 bp separated by a pair of 18,861 bp inverted repeats (IRa and IRb). The composition, gene order, and AT-content in the S. montanum plastome are similar to that of a typical flowering plant pt DNA. One hundred fourteen unique genes have been identified, including 30 tRNA genes, four rRNA genes, and 80 protein genes. Of 18 intron-containing genes found, 16 genes have one intron, and two genes (ycf3, clpP) have two introns. Comparative analysis of Apiaceae plastomes reveals in the S. montanum plastome a LSC/IRb junction shift, so that the part of the ycf2 (4980 bp) gene is located in the LSC, but the other part of ycf2 (1301 bp) is within the inverted repeat. Thus, structural rearrangements in the plastid genome of S. montanum result in an enlargement of the LSC region by means of capture of a large part of ycf2, in contrast to eight Apiaceae plastomes where the complete ycf2 gene sequence is located in the inverted repeat. 相似文献