منابع مشابه
Telomere stability and carcinogenesis: an off-again, on-again relationship.
Previous studies in mice have demonstrated antagonistic effects of telomerase loss on carcinogenesis. Telomere attrition can promote genome instability, thereby stimulating initiation of early-stage cancers, but can also inhibit tumorigenesis by promoting permanent cell growth arrest or death. Human cancers likely develop in cell lineages with low levels of telomerase, leading to telomere losse...
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In bacteria, a fundamental level of gene regulation occurs by competitive association of promoter-specificity factors called sigmas with RNA polymerase (RNAP). This sigma cycle paradigm underpins much of our understanding of all transcriptional regulation. Here, we review recent challenges to the sigma cycle paradigm in the context of its essential features and of the structural basis of sigma ...
متن کاملT helper cell differentiation: on again, off again.
Recent studies raise the possibility that T helper (Th) polarization may be attributable to generalized activation and regulated silencing rather than regulated activation of target cytokine genes. The binding of transcription factors GATA-3 or T-bet to specific enhancers does recruit transcription factors such as NFAT-1 to IL-4 or IFNgamma promoters, respectively; however, GATA-3 also intrinsi...
متن کاملOn-again/off-again dating relationships: what keeps partners coming back?
Building on research comparing on-again/off-again (on-off) relationships to other dating relationships, the current study focused on a unique feature of these relationships-renewals. A sample of 274 participants who had experienced an on-off relationship completed a survey about why they renewed their relationships, characteristics of their breakups and renewals, and what stressors and benefits...
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ژورنال
عنوان ژورنال: Nature
سال: 1989
ISSN: 0028-0836,1476-4687
DOI: 10.1038/338365b0