Nascent transcripts

Transcription continues into the AT region, and with the aid of the p termination protein the RNA polymerase stops, dissociates from the DNA template, and releases the nascent transcript. 

Stuart, K., RNA editing in mitochondrial mRNA of trypanoso-matids. Trends Biochem. Sci. 16 68-72, 1991. RNA editing is processing that involves the removal, addition, and modification of nucleotides in the coding regions of nascent transcripts. 

Splicing necessary to convert nascent transcripts is often a highly regulated process. 

Figure 1 Generalized model for sensing regulatory effectors by nascent mRNA leader transcripts. Transcription attenuation mechanisms have been identified in which the nascent transcript interacts with a translating 70S ribosome, a protein, an RNA molecule or a small metabolite, (a) Binding of the effector molecule promotes transcription termination, (b) Binding of the effector molecule promotes transcription readthrough (antitermination). See text for details.

The most recently identified class of transcription attenuation mechanism involves direct sensing of the effector molecule by the nascent transcript (52-54). These RNA sensors control metabolically diverse pathways. As for the other attenuation and antitermination mechaiusms discussed thus far, recognition of the particular effector molecule occurs with the appropriate affinity and high specificity required for precise control of gene expression. 

Intron. A segment of the nascent transcript that is removed by splicing. Also refers to the corresponding region in the DNA. Synon)nnous with intervening sequence. 

Following transcription, the nascent transcript is transported out of the nucleus and into the cytoplasm where it is converted to an siRNA by Dicer. 

Are nascent transcripts retained by the pronuclei and not exported to the cytoplasm Following injection of BrUTP into living, one-cell embryos, transcripts are... 

The precise base pair where RNA polymerase II initiates transcription in the adenovirus late transcription unit was determined by analyzing the RNAs synthesized during in vitro transcription of adenovirus DNA restriction fragments that extended somewhat upstream and downstream of the approximate initiation region determined by nascent-transcript analysis. The rationale of this experiment and typical results are illustrated in Figure 11-8. The RNA transcripts synthesized in vitro by RNA polymerase II from the... 

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