Abstract:
:Specific active transcription units on chromosome IV in the salivary glands of Chironomus tentans have been visualized by the Miller spreading technique and in situ by conventional electron microscopy. These units are likely to be located in the two most conspicuous puffs on chromosome IV, Balbiani ring 1 (BR 1) and Balbiani ring 2 (BR 2). The transcription units in these Balbiani rings generate 75S RNA molecules constituting putative messenger RNA species for the predominant cellular product, the salivary polypeptides. Solitary active transcription units with a mean length of 7.7 micron were observed most frequently. The lateral ribonucleoprotein (RNP) fibers of each unit formed a single length gradient. The number of fibers per unit was 123 (+/- 24), or about 16 growing RNP fibers per micron of chromosome fiber. The considerable variation in the number of RNP fibers per unit suggests that transcription can be modulated at the level of the individual gene. The modulation is probably achieved via the initiation event and/or via an early pretermination step, but a change in the elongation rate could not be excluded. The number of polymerases starting to traverse the whole gene was estimated to be six per min and transcription unit, and the rate of RNA chain elongation was calculated to be 31 nucleotides per second at 18 degrees C. The properties of the chromosome fiber within the active 75S RNA units and also within their vicinity were studied in the Miller spreads. The inactive chromosome fiber exhibited a uniform beaded conformation, while the active fiber was sparsely and irregularly beaded. Furthermore, the chromosome fiber was more extended in the active 75S RNA unit than in inactive regions (DNA packing ratios of 1.6 and 1.9, respectively). By comparing the properties of the active 75S RNA gene with those of active genes in other systems, it was inferred that the loss of beads and the extension of the fiber in the active unit is probably directly related to the level of transcriptive activity. Finally, a smooth nonbeaded segment of 0.18 micron in length was found to precede the RNP fiber gradient. This segment may have a role in the process of transcriptional regulation. On the basis of comparison with the active transcription units in spread preparations. It was possible to identify active units in the Balbiani rings in sectioned material using conventional electron microscopy. In both BR 1 and BR 2 an active unit appeared as a loop, consisting of a fiber axis and having RNP granules attached to the loop axis by stalks. The growing RNP fibers therefore seem to be organized into granular structures during the transcription process, and the final products in BR 1 and BR2 are granules, 500 A in diameter, each containing a 75S RNA molecule.
journal_name
Celljournal_title
Cellauthors
Lamb MM,Daneholt Bdoi
10.1016/0092-8674(79)90324-6subject
Has Abstractpub_date
1979-08-01 00:00:00pages
835-48issue
4eissn
0092-8674issn
1097-4172pii
0092-8674(79)90324-6journal_volume
17pub_type
杂志文章相关文献
CELL文献大全abstract::Temperature-sensitive mutants of vesicular stomatitis virus (VSV) belonging to complementation group III contain a lesion in the matrix (M) protein. This results in a 2--5 fold increase in transcription at the nonpermissive temperature. Co-infection of cells with one of these mutants and wild-type virus reverses this ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(78)90069-7
更新日期:1978-12-01 00:00:00
abstract::We report here the identification of thyroid hormone response elements (TREs) that consist of a direct repeat, not a palindrome, of the half-sites. Unlike palindromic TREs, direct repeat TREs do not confer a retinoic acid response. The tandem TRE can be converted into a retinoic acid response element by increasing the...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(91)90020-y
更新日期:1991-06-28 00:00:00
abstract::Membrane scission is essential for intracellular trafficking. While BAR domain proteins such as endophilin have been reported in dynamin-independent scission of tubular membrane necks, the cutting mechanism has yet to be deciphered. Here, we combine a theoretical model, in vitro, and in vivo experiments revealing how ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2017.05.047
更新日期:2017-06-29 00:00:00
abstract::The origin of a low molecular weight virus-associated RNA (VA-RNA) was mapped by hybridization of VA-RNA to specific fragments of adenovirus type 2 DNA, obtained after cleavage with three different restriction endonucleases. VA-RNA was found to hybridize exculsively to the l-strand [strand with low buoyant density in ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(75)90066-5
更新日期:1975-09-01 00:00:00
abstract::In the SV40-transformed mouse embryo fibroblast cell line SVT2/S, genomic rearrangements involving the SV40 DNA and flanking host sequences were identified by Southern blot hybridization using viral DNA as probe. No rearrangements of SV40 DNA integrated into nonpermissive mouse cells have been previously described. Th...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(81)90268-3
更新日期:1981-01-01 00:00:00
abstract::The 5' terminal structure of the mRNA synthesized in vitro by the virion-associated RNA polymerase of vesicular stomatitis virus in the presence of S-adenosyl-L-methione consists of 7-methyl guanosine linked to 2'-O-methyl adenosine through a 5'-5' pyrophosphate bond as m7G(5')ppp(5')A-m-p ... The alpha and beta phosp...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(75)90091-4
更新日期:1975-05-01 00:00:00
abstract::Recent work has identified a cascade of membrane bound protein kinases in Ehrlich ascites tumor cells. These enzymes, designated PKL, PKS and PKM, are present in both Ehrlich tumor and mouse brain, but the cascade is active only in the tumor tissue. We have now purified a fourth protein kinase, PKF, that is also assoc...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(81)90227-0
更新日期:1981-07-01 00:00:00
abstract::In this issue of Cell, Noma et al. (2006) show that B-boxes and TFIIIC limit the spread of heterochromatin at the silent mat region in the fission yeast genome. Global analysis of TFIIIC distribution revealed dispersed sites of association that coalesce at the nuclear periphery, suggesting that TFIIIC may act as a bar...
journal_title:Cell
pub_type: 评论,杂志文章,评审
doi:10.1016/j.cell.2006.05.016
更新日期:2006-06-02 00:00:00
abstract::32P-labeled cowpea mosaic virus (CPMV) RNAs were analyzed for their 5' termini by three different fingerprinting standard procedures. These analyses showed unequivocally that CPMV RNAs lack a structure like m7GpppN ... at their 5' termini. In addition, neither mono-, di- or triphosphorylated [(p)(p)pN ....] termini we...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(77)90318-x
更新日期:1977-05-01 00:00:00
abstract::Vertebrate Hoxd genes are sequentially activated during the morphogenesis and pattern formation of the limb. Using the approach of gene disruption via homologous recombination in embryonic stem cells, we have assessed the function of the last gene of the complex, Hoxd-13. Mutant mice displayed skeletal alterations alo...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(93)90378-4
更新日期:1993-11-05 00:00:00
abstract::Ventral midline cells at different rostrocaudal levels of the central nervous system exhibit distinct properties but share the ability to pattern the dorsoventral axis of the neural tube. We show here that ventral midline cells acquire distinct identities in response to the different signaling activities of underlying...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/s0092-8674(00)80334-7
更新日期:1997-07-25 00:00:00
abstract::A recent report proposed a function of the ubiquitin conjugation factors Rad6 and Rad18 comparable to the bacterial SOS response, controlling damage-induced transcriptional activation and contributing to checkpoint signaling. The relevant ubiquitylation target was identified as budding yeast Rad17, a subunit of the PC...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2010.04.039
更新日期:2010-06-11 00:00:00
abstract::Previous work from our laboratory has demonstrated that a subclass of the aminoglycoside antibiotics, those containing the drug fragment paromamine, stimulates mistranslation in cell-free protein-synthesizing systems derived from eucaryotic cells. We report here experiments which show that the ciliate Tetrahymena ther...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(78)90201-5
更新日期:1978-02-01 00:00:00
abstract::The asymmetries of internal organs are consistently oriented along the left-right axis in all vertebrates, and perturbations of left-right orientation lead to significant congenital disease. We propose a model in which a "left-right coordinator" interacts with the Spemann organizer to coordinate the evolutionarily con...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/s0092-8674(00)81144-7
更新日期:1998-04-03 00:00:00
abstract::The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell ...
journal_title:Cell
pub_type: 杂志文章,评审
doi:10.1016/j.cell.2011.02.013
更新日期:2011-03-04 00:00:00
abstract::Regulatory T cells (Tregs) play a pivotal role in the inhibition of anti-tumor immune responses. Understanding the mechanisms governing Treg homeostasis may therefore be important for development of effective tumor immunotherapy. We have recently demonstrated a key role for the canonical nuclear factor κB (NF-κB) subu...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2017.08.004
更新日期:2017-09-07 00:00:00
abstract::Cholera toxin is assembled from two subunits in the periplasm of Vibrio cholerae and disassembled in the analogous compartment of target cells, the lumen of the endoplasmic reticulum (ER), before a fragment of it, the A1 chain, is transported into the cytosol. We show that protein disulfide isomerase (PDI) in the ER l...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/s0092-8674(01)00289-6
更新日期:2001-03-23 00:00:00
abstract::Protein aggregation is linked with neurodegeneration and numerous other diseases by mechanisms that are not well understood. Here, we have analyzed the gain-of-function toxicity of artificial β sheet proteins that were designed to form amyloid-like fibrils. Using quantitative proteomics, we found that the toxicity of ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2010.11.050
更新日期:2011-01-07 00:00:00
abstract::Transcriptional regulation in the galactose regulon of yeast is determined by an interplay between a positive regulatory protein, GAL4, and a negative regulatory protein, GAL80. We show that derivatives of GAL4 missing as few as 28 carboxy-terminal amino acids are not responsive to GAL80 regulation, implying that the ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(87)90671-4
更新日期:1987-07-03 00:00:00
abstract::A basic B-cell-specific protein of 35,000 daltons (XM1) is expressed at a high rate--comparable to actin--in resting splenic B lymphocytes of various species. Splenic or thymic T cells or fibroblasts do not express this protein. Upon polyclonal stimulation of B lymphocytes or in proliferating B-lymphocyte-derived cell...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(82)90162-3
更新日期:1982-06-01 00:00:00
abstract::The tumor microenvironment is known to play an important role in tumorigenesis. In this issue, Yang et al. (2008) demonstrate that mast cells heterozygous for the Nf1 gene promote the growth of neurofibromas in a mouse model of neurofibromatosis and that genetic and pharmacological inhibition of these cells is suffici...
journal_title:Cell
pub_type: 评论,杂志文章
doi:10.1016/j.cell.2008.10.009
更新日期:2008-10-31 00:00:00
abstract::The nucleotide sequence from the 5' terminus inward of one third of mouse alpha- and beta maj-globin messenger RNAs has been established. In addition, using 5' 32P end-labeled mRNAs as substrates and S1 and T1 nucleases as probes for single-stranded regions, the secondary structures of mouse and rabbit alpha- and beta...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(80)90391-8
更新日期:1980-01-01 00:00:00
abstract::Understanding human embryonic ventral midbrain is of major interest for Parkinson's disease. However, the cell types, their gene expression dynamics, and their relationship to commonly used rodent models remain to be defined. We performed single-cell RNA sequencing to examine ventral midbrain development in human and ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2016.09.027
更新日期:2016-10-06 00:00:00
abstract::The exchange of metabolites between the mitochondrial matrix and the cytosol depends on β-barrel channels in the outer membrane and α-helical carrier proteins in the inner membrane. The essential translocase of the inner membrane (TIM) chaperones escort these proteins through the intermembrane space, but the structura...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2018.10.039
更新日期:2018-11-15 00:00:00
abstract::The lin-12 gene of C. elegans and the Notch gene of D. melanogaster encode structurally related transmembrane proteins that mediate intercellular signaling. We show that truncated forms of these proteins consisting of only the intracellular domains cause cell fate transformations associated with constitutive activity ...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(93)90424-o
更新日期:1993-07-30 00:00:00
abstract::Certain mutations can cause proteins to accumulate in neurons, leading to neurodegeneration. We recently showed, however, that upregulation of a wild-type protein, Ataxin1, caused by haploinsufficiency of its repressor, the RNA-binding protein Pumilio1 (PUM1), also causes neurodegeneration in mice. We therefore search...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2018.02.006
更新日期:2018-02-22 00:00:00
abstract::We have tested the hypothesis that DNA methylation patterns are replicated in the somatic cells of vertebrates. Using M-Hpa II, the modification enzyme from Haemophilus parainfluenzae which methylates the internal cytosine residues in the sequence 5'CCGG 3' GGCC, we methylated bacteriophage phi X174 RF DNA and the clo...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(81)90498-0
更新日期:1981-04-01 00:00:00
abstract::Repair of DNA double-strand breaks (DSBs) by non-homologous end joining is critical for neural development, and brain cells frequently contain somatic genomic variations that might involve DSB intermediates. We now use an unbiased, high-throughput approach to identify genomic regions harboring recurrent DSBs in primar...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/j.cell.2015.12.039
更新日期:2016-02-11 00:00:00
abstract::Recombinant E. coli that produce light were found in a clone library of hybrid plasmids containing DNA from the marine bacterium Vibrio fischeri. All luminescent clones had a 16 kb insert that encoded enzymatic activities for the light reaction as well as regulatory functions necessary for expression of the luminescen...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(83)90063-6
更新日期:1983-03-01 00:00:00
abstract::E2F is a transcription factor believed to play a role in the activation of genes required for cellular proliferation. Its regulation is likely important for maintenance of G0 and for the initiation of cell growth. The retinoblastoma product (RB) forms a complex with E2F in G1 in primary and established human cells. As...
journal_title:Cell
pub_type: 杂志文章
doi:10.1016/0092-8674(92)90214-w
更新日期:1992-01-10 00:00:00