Acclaimed as a great beauty, she became established as a leading lady. She was named after a beloved uncle, who died young. Their father was a successful insurance broker of Irish descent, their mother a former physical education instructor. Tierney was raised in Westport, Connecticut. She attended St. She published her first poem, entitled "Night", in the school magazine and wrote poetry occasionally throughout her life.
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Herpesvirus envelopment is a two-step process which includes acquisition of a primary envelope resulting from budding of intranuclear capsids through the inner nuclear membrane. Fusion with the outer leaflet of the nuclear membrane releases nucleocapsids into the cytoplasm, which then gain their final envelope by budding into trans -Golgi vesicles. It has been shown that the UL34 gene product is required for primary envelopment of the alphaherpesvirus pseudorabies virus PrV B. Klupp, H.
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This page has been archived and is no longer updated. DNA is double-stranded, but only one strand serves as a template for transcription at any given time. This template strand is called the noncoding strand. The nontemplate strand is referred to as the coding strand because its sequence will be the same as that of the new RNA molecule. In most organisms, the strand of DNA that serves as the template for one gene may be the nontemplate strand for other genes within the same chromosome. Polymerases are large enzymes composed of approximately a dozen subunits, and when active on DNA, they are also typically complexed with other factors.
With the understanding that all cells of an organism carry the same DNA, and with increased knowledge of mechanisms of gene expression, the definition was changed to focus on ways in which heritable traits can be associated not with changes in nucleotide sequence, but with chemical modifications of DNA, or of the structural and regulatory proteins bound to it. Recent discoveries about the role of these mechanisms in early development may make it desirable to return to the original definition of epigenetics. The history of epigenetics is linked with the study of evolution and development. More recently added to this definition is the constraint that initiation of the new epigenetic state should involve a transient mechanism separate from the one required to maintain it Berger et al. Until the s, however, the word epigenetics was used more broadly and less precisely to categorize all of the developmental events leading from the fertilized zygote to the mature organism—that is, all of the regulated processes that, beginning with the genetic material, shape the final product Waddington This concept had its origins in the much earlier studies in cell biology and embryology, beginning in the late 19th century, which laid the groundwork for our present understanding of the relationship between genes and development. There was a long debate among embryologists about the nature and location of the components responsible for carrying out the developmental plan of the organism. These views focused on the relative importance of the nucleus and cytoplasm in the developmental process. Although the definition that we choose for epigenetics has changed to accommodate our increasing knowledge, it is important to remember that the original problem was: How can a single fertilized egg give rise to a complex organism with cells of varied phenotypes?