Tat stimulates human immunodeficiency virus type 1 (HIV-1) transcription elongation through recognition of the transactivation response (TAR) RNA stem-loop structure at the 5' end of nascent viral transcripts. Recently, a human transcription elongation factor P-TEFb, consisting of CDK9 kinase, cyclin T and other associated factors, has been shown to interact with Tat to restore Tat activation i...

The telomerase enzyme plays a critical role in human aging and cancer biology by maintaining telomere length and extending the proliferative lifespan of most stem cells and cancer cells. Despite the importance of this enzyme, our understanding of the mechanisms that regulate its activity and establish telomere length homeostasis in mammalian cells is incomplete, in part because the perfect repe...

Plants respond to neighbor shade by increasing stem and petiole elongation. Shade, sensed by phytochrome photoreceptors, causes stabilization of PHYTOCHROME INTERACTING FACTOR proteins and subsequent induction of YUCCA auxin biosynthetic genes. To investigate the role of YUCCA genes in phytochrome-mediated elongation, we examined auxin signaling kinetics after an end-of-day far-red (EOD-FR) lig...

Natural cellulose fibers with cellulose content, strength, and elongation higher than that of milkweed floss and between that of cotton and linen have been obtained from the stems of common milkweed plants. Although milkweed floss is a unique natural cellulose fiber with low density, the short length and low elongation make milkweed floss unsuitable as a textile fiber. The possibility of using ...

HIV gene expression is subject to a transcriptional checkpoint, whereby negative transcription elongation factors induce an elongation block that is overcome by HIV Tat protein in conjunction with P-TEFb. P-TEFb is a cyclin-dependent kinase that catalyzes Tat-dependent phosphorylation of Ser-5 of the Pol II C-terminal domain (CTD). Ser-5 phosphorylation confers on the CTD the ability to recruit...

Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch elongation and milkweed growth and pod formation were significantly higher west of Lake Mic...

As every student of plant biology learns, gibberellin (GA) was first isolated in Japan in the 1930s from a fungus that causes a serious disease in rice, called “foolish seedling disease” ( bakanae-byo ) by Japanese farmers. Afflicted plants were characterized by excessive growth of seedlings and a decline in seed production in mature plants. The purified active compound was named for the fungus...

in order to study grain yield, yield components and growth indices in wheat, the experiment was carried out with five wheat cultivars at rbcd arrangement with 4 replications at gorgan university of agricultural sciences and natural resources. the cultivars included zagros, tajan, kohdasht, durum and n81-18 line. to measure studied traits (leaf, stem and shoot dried weight and leaf area) fifteen...

Reciprocal grafts, and applications of gibberellin (GA) and indoleacetic acid (IAA) were used to localize the site of control for stem elongation in cucumber (Cucumis sativus L.). Dwarf and tall plants were reciprocally grafted to determine influence of stems and roots on stem elongation. At 21 days there were no significant differences in length between stems grafted to their own roots and tho...

As every student of plant biology learns, gibberellin (GA) was first isolated in Japan in the 1930s from a fungus that causes a serious disease in rice, called “foolish seedling disease” ( bakanae-byo ) by Japanese farmers. Afflicted plants were characterized by excessive growth of seedlings and a decline in seed production in mature plants. The purified active compound was named for the fungus...