An intact histone 3'-processing site is required for transcription termination in a mouse histone H2a gene

A transcription termination site has been characterized between the mouse histone H2a-614 and H3-614 genes. There is a poly(A)- RNA present in small amounts in the nucleus which ends 600 nucleotides 3' to the H2a-614 gene. Nuclear transcription studies demonstrate that transcription extends at least 600 nucleotides 3' to the gene but is greatly reduced 700 nucleotides 3' to the gene. If all or part of the normal 3'-processing signal, consisting of the stem-loop and the U7 small nuclear ribonucleoprotein binding site, is deleted, transcription then continues past the putative termination site and RNAs which end at the 3' end of the downstream H3-614 gene accumulate. Insertion of a 150-nucleotide fragment containing the termination site between the histone 3' end and downstream polyadenylation sites reduces usage of polyadenylation sites 85 to 90%. Taken together these results suggest there is a transcription termination site which requires an intact histone 3'-processing signal to function.

An intact histone 3'-processing site is required for transcription termination in a mouse histone H2a gene.

A transcription termination site has been characterized between the mouse histone H2a-614 and H3-614 genes. There is a poly(A)- RNA present in small amounts in the nucleus which ends 600 nucleotides 3' to the H2a-614 gene. Nuclear transcription studies demonstrate that transcription extends at least 600 nucleotides 3' to the gene but is greatly reduced 700 nucleotides 3' to the gene. If all or part of the normal 3'-processing signal, consisting of the stem-loop and the U7 small nuclear ribonucleoprotein binding site, is deleted, transcription then continues past the putative termination site and RNAs which end at the 3' end of the downstream H3-614 gene accumulate. Insertion of a 150-nucleotide fragment containing the termination site between the histone 3' end and downstream polyadenylation sites reduces usage of polyadenylation sites 85 to 90%. Taken together these results suggest there is a transcription termination site which requires an intact histone 3'-processing signal to function.

Attenuation of transcription of biotin genes in Escherichia coli

The nature of RNA synthesis from the divergent bioA:BFCD operon has been studied in vivo in Escherichia coli minicells. Minicells containing bio-recombinant plasmids produce 96 nucleotide long RNA. This small RNA was characterized by blotting on diazobenzyloxymethyl cellulose paper and hybridization with the appropriate bio-probe DNA. Determination of β-galactosidase, using biotin requiring mutant cells of E. coli JM101 infected with a bio-M13 recombinant phage containing the functional bioB region of the operon, demonstrated the presence of a transcription termination site in the bioBFCD segment. There was a three- to five-fold reduction in β-galactosidase activity in this system at an appropriate d-biotin concentration which indicated that the early termination of transcription is biotin dependent. From the nucleotide sequence of the promoter proximal region of the bioB gene, a 13-oligonucleotide sequence believed to be the early transcription termination site has been located. A model of regulation at termination has been proposed on the basis of the not-too-stable RNA secondary structure at the site of early termination of transcription.

Regulatory region of the Klebsiella aerogenes tryptophan operon

The trp operon of Klebsiella aerogenes was cloned, and its regulatory region was sequenced. Comparison with previously reported trp regulatory sequences of other enteric bacteria indicates that the K. aerogenes trp promoter-operator region is most similar to the corresponding region of Salmonella typhimurium. The trp leader regions of K. aerogenes and other enteric bacteria are organized similarly, but there are significant differences in the stabilities of the predicted secondary structures in their leader transcripts. These differences should make the K. aerogenes attenuator a weaker transcription termination site than any of the other attenuator regions studied; this was confirmed in in vitro transcription experiments. The sequence of the leader transcript and the precise site of in vitro termination were determined.