We have examined elongation by RNA polymerase II initiated at a promoter and have identified two classes of elongation complexes. Following initiation at a promoter, all polymerase molecules enter an abortive mode of elongation. Abortive elongation is characterized by the rapid generation of short transcripts due to pausing of the polymerase followed by termination of transcription. Termination...

Arabinogalactan proteins (AGP) are a class of cell surface plant peptidoglycans which have been implicated in root elongation and signal transduction pathways. AGPs function not only as markers of cellular identity but also as signaling molecules, which might initiate signal transduction. Aluminum promotes the elongation of tea (Camellia sinensis L.) roots. Although some mechanisms by which Al ...

We used a video digitizer system to (a) measure changes in the pattern of longitudinal surface extension in primary roots of maize (Zea mays L.) upon application and withdrawal of auxin and (b) compare these patterns during gravitropism in control roots and roots pretreated with auxin. Special attention was paid to the distal elongation zone (DEZ), arbitrarily defined as the region between the ...