ISSN:0265-9247    

DOI:10.1002/bies.950030602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractThe mechanism(s) by which the thymidine analogue 5‐bromodeoxyuridine (BUdR) specifically inhibits the expression of differentiated functions is poorly understood, as are the ways in which cells regulate processes exhibiting probabilistic aspects. I have developed a theoretical model for the regulation of the decision of myogenic cells to differentiate that can explain both of the above phenomena. This model provided a strategy for isolating myoblast variants that had amplified the expression of the factors regulating the decision to differentiate. These myoblasts served as the source of mRNA for making and screening a cDNA library in order to isolate these factors. The successful cloning of these genes should represent a major advance in our understanding of the molecular basis for the major coordinated changes in gene expression that accompany cell differentiatio

ISSN:0265-9247    

DOI:10.1002/bies.950030603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractGene transcription in eukaryotes is associated with conformational changes of a large area of chromatin adjacent to a gene. This rearrangement may involve the whole loop (topological domain) to which a given gene belongs.Regulatory events associated with activation or inactivation of transcription are found to act through relatively short nucleotide sequences, often located several thousand base pairs apart from gene. These sequences, termed enhancers may act independently on their distance from or orientation with respect to the gene.Both long‐range conformational rearrangements of chromatin and any long distance effects of enhancers may be associated with elastic torsional strain in DNA, arising in transcriptionally active chromatin loops. Enhancer effects, in particular, may be associated with conformational transitions in DNA competing for the energy deposited in the elastic spring of the DN

ISSN:0265-9247    

DOI:10.1002/bies.950030604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractMuch of the recent work on oncogenes has been interpreted as signifying that the cancerous phenotype is caused by the direct expression of ‘dominantly‐acting’ oncogenes. On the other hand, numerous somatic cell hybridization experiments suggest that there are potent tumour‐suppressor genes in the genome. The conflict between the observations and the possible nature of the relationships between oncogenes and tumour‐suppressor are

ISSN:0265-9247    

DOI:10.1002/bies.950030605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractStudies of the regulation of heme oxygenase by synthetic metalloporphyrins reveal that within this group of compounds there exist both inducers and inhibitors of the synthesis of this enzyme or of its catalytic function. The ability of metalloporphyrins to alter heme catabolism is of considerable experimental and clinical interest since such alterations may have consequences for other aspects of heme homeostasis, including its synthesis and its function in the form of cytochrome(s) P‐450. Examples of the metabolic effects – and their potential clinical and pharmacological consequences – produced by two synthetic metalloporphyrins, Sn‐protoporphyrin and Co‐protoporphyrin, are

ISSN:0265-9247    

DOI:10.1002/bies.950030606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950030607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractTwo types of interleukin 1 (IL‐1α and IL‐1β) have been defined by purifying the molecules from activated human peripheral blood cells, followed by cloning and expressing the molecules in Escherichia coli. Both types of IL‐1 stimulate proliferation and differentiation of T‐ and B‐lymphocytes and induce cartilage proteoglycan degradation but differ in other properties. For example, demineralization and appears to be a major mediator in the pathogenesis of joint erosion in rheumatoid arthritis. Synthetic adjuvants elicit the production of IL‐1 separate from endogenous pyrogen, and this property is required for the new generation of vaccines based on antigens produced by recombinant D

ISSN:0265-9247    

DOI:10.1002/bies.950030608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractEukaryotic genes are divided into three categories according to the machineries by which they are transcribed. Ribosomal RNA genes (rDNA) are the only ones that are transcribed by RNA polymerase I and are under different control from other genes transcribed by RNA polymerase II or III. None the less, the regulation of rDNA is of prime interest in view of its close relationship to cell growth and differentiation. In this review I shall discuss the recent progress in the study of transcription mechanisms of rDNA by the RNA polymerase I system. The structure of the rDNA promoter and the presence of possible upstream enhancer regions will be described. In addition, factors involved in the transcription initiation of this gene will be discussed with special reference to the formation of an initiation complex.

ISSN:0265-9247    

DOI:10.1002/bies.950030609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractFor many years, there has been a gap in our capacity to study the structure and organization of chromosomal DNA molecules. The very small genomes of some viruses and bacteriophages (≤ 50,000 bp or 50 kb) are amenable to analysis by conventional gel electrophoresis, while the extremely large DNA molecules (>100,000 kb) comprising the chromosomes of higher eukaryotes have been analysed under the light microscope, using a range of banding and in situ hybridization techniques. However, intact DNA molecules with sizes between these two extremes have been largely inaccessible experimentally. This gap has recently been bridged with the development of two‐dimensional electrophoretic procedures that allow the separation and purification of chromosome‐sized DNA molecules ranging from ∼ 50 kb to several thousand kb.1–3There are currently two variations of the technique in use: pulsed field gradient (PFG) gel electrophoresis1,2and orthogonal‐field‐alteration gel electrophoresis (OFAGE).3Both are based on a common principle, differing primarily in the geometry of the electrodes. Already, they have been employed to determine the approximate chromosome sizes and numbers for a variety of lower eukaryotes, including yeast and several protozoa.2–10These ‘molecular karyotypes’ provide fundamental information about the genomic organization of each organism, and allow very rapid construction of linkage maps. Surprisingly, they have also revealed a remarkable plasticity in the genomes of sever

ISSN:0265-9247    

DOI:10.1002/bies.950030610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950030611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY