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Bicistronic and fused monocistronic transcripts are derived from adjacent loci in the Arabidopsis genome.

ABSTRACT: Comparisons of full-length cDNAs and genomic DNAs available for Arabidopsis thaliana described here indicate that some adjacent loci are transcribed into extremely long RNAs spanning two annotated genes. Once expressed, some of these transcripts are post-transcriptionally spliced within their coding and intergenic sequences to generate bicistronic transcripts containing two complete open reading frames. Others are spliced to generate monocistronic transcripts coding for fusion proteins with sequences derived from both loci. RT-PCR of several P450 transcripts in this collection indicates that these extended transcripts exist side by side with shorter monocistronic transcripts derived from the individual loci in each pair. The existence of these unusual transcripts highlights variations in the processes of transcription and splicing that could not possibly have been predicted in the algorithms used for genome annotation and splice site predictions.

SUBMITTER: Thimmapuram J

PROVIDER: S-EPMC1370702 | biostudies-literature | 2005 Feb

REPOSITORIES: biostudies-literature

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Bicistronic and fused monocistronic transcripts are derived from adjacent loci in the Arabidopsis genome.

Thimmapuram Jyothi J Duan Hui H Liu Lei L Schuler Mary A MA

RNA (New York, N.Y.) 20050201 2

Comparisons of full-length cDNAs and genomic DNAs available for Arabidopsis thaliana described here indicate that some adjacent loci are transcribed into extremely long RNAs spanning two annotated genes. Once expressed, some of these transcripts are post-transcriptionally spliced within their coding and intergenic sequences to generate bicistronic transcripts containing two complete open reading frames. Others are spliced to generate monocistronic transcripts coding for fusion proteins with sequ ...[more]

PMID: 15659355

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Project description:Inverse PCR was used to amplify major cold shock protein (MCSP) gene families from a diverse range of bacteria, including the psychrotolerant Yersinia enterocolitica, which was found to have two almost identical MCSP coding regions (cspA1 and cspA2) located approximately 300 bp apart. This tandem gene duplication was also found in Y. pestis, Y. pseudotuberculosis, and Y. ruckeri but not in other bacteria. Analysis of the transcriptional regulation of this MCSP gene in Y. enterocolitica, performed by using both reverse transcriptase-PCR and Northern blot assays, showed there to be two cold-inducible mRNA templates arising from this locus: a monocistronic template of approximately 450 bp (cspA1) and a bicistronic template of approximately 900 bp (cspA1/A2). The former may be due to a secondary structure between cspA1 and cspA2 causing either 3' degradation protection of cspA1 or, more probably, partial termination after cspA1. Primer extension experiments identified a putative transcriptional start site (+1) which is flanked by a cold-box motif and promoter elements (-10 and -35) similar to those found in Escherichia coli cold-inducible MCSP genes. At 30 degrees C, the level of both mRNA molecules was negligible; however, upon a temperature downshift to 10 degrees C, transcription of the bicistronic mRNA was both substantial (300-fold increase) and immediate, with transcription of the monocistronic mRNA being approximately 10-fold less (30-fold increase) and significantly slower. The ratio of bicistronic to monocistronic mRNA changed with time after cold shock and was higher when cells were shocked to a lower temperature. High-resolution, two-dimensional protein gel electrophoresis showed that synthesis of the corresponding proteins, both CspA1 and CspA2, was apparent after only 10 min of cold shock from 30 degrees C to 10 degrees C. The data demonstrate an extraordinary capacity of the psychrotolerant Y. enterocolitica to produce major cold shock proteins upon cold shock.

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Dataset Information

Bicistronic and fused monocistronic transcripts are derived from adjacent loci in the Arabidopsis genome.

Publications

Bicistronic and fused monocistronic transcripts are derived from adjacent loci in the Arabidopsis genome.

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