While studying the gene expression of the Sulfolobus spindle-shaped virus 1 (SSV1) in Sulfolobus solfataricus lysogenic cells, a novel viral transcript (T-lys) was identified. Transcriptional analysis revealed that T-lys is expressed only in the absence of UV irradiation and is downregulated during the growth of the lysogenic host. The correponding gene f55 lies between two transcriptional units (T-6 and T-ind) that are upregulated upon UV irradiation. The open reading frame f55 encodes a 6.3-kDa protein which shows sequence identity with negative regulators that fold into the ribbon-helix-helix DNA-binding motif. DNA-binding assays demonstrated that the recombinant F55, purified from Escherichia coli, is indeed a putative transcription factor able to recognize site specifically target sequences in the promoters of the early induced T-5, T-6, and T-ind transcripts, as well as of its own promoter. Binding sites of F55 are included within a tandem-repeated sequence overlapping the transcription start sites and/or the B recognition element of the pertinent genes. The strongest binding was observed with the promoters of T-5 and T-6, and an apparent cooperativity in binding was observed with the T-ind promoter. Taking together the transcriptional analysis data and the biochemical evidences, we surmise that the protein F55 is involved in the regulation of the lysogenic state of SSV1.

T(lys), a newly identified Sulfolobus spindle-shaped virus 1 transcript expressed in the lysogenic state, encodes a DNA-binding protein interacting at the promoters of the early genes

Fusco, Salvatore;
2013-01-01

Abstract

While studying the gene expression of the Sulfolobus spindle-shaped virus 1 (SSV1) in Sulfolobus solfataricus lysogenic cells, a novel viral transcript (T-lys) was identified. Transcriptional analysis revealed that T-lys is expressed only in the absence of UV irradiation and is downregulated during the growth of the lysogenic host. The correponding gene f55 lies between two transcriptional units (T-6 and T-ind) that are upregulated upon UV irradiation. The open reading frame f55 encodes a 6.3-kDa protein which shows sequence identity with negative regulators that fold into the ribbon-helix-helix DNA-binding motif. DNA-binding assays demonstrated that the recombinant F55, purified from Escherichia coli, is indeed a putative transcription factor able to recognize site specifically target sequences in the promoters of the early induced T-5, T-6, and T-ind transcripts, as well as of its own promoter. Binding sites of F55 are included within a tandem-repeated sequence overlapping the transcription start sites and/or the B recognition element of the pertinent genes. The strongest binding was observed with the promoters of T-5 and T-6, and an apparent cooperativity in binding was observed with the T-ind promoter. Taking together the transcriptional analysis data and the biochemical evidences, we surmise that the protein F55 is involved in the regulation of the lysogenic state of SSV1.
2013
DNA, Archaeal; Protein Binding; Sulfolobus solfataricus; Transcription Factors; Gene Expression Regulation, Viral; Lysogeny; Promoter Regions, Genetic; Transcription, Genetic
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Descrizione: Fusco et al. 2013 Journal of Virology
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11562/1010954
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