TY - JOUR

T1 - Tlys, 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

AU - Fusco, Salvatore

AU - She, Qunxin

AU - Bartolucci, Simonetta

AU - Contursi, Patrizia

PY - 2013

Y1 - 2013

N2 - While studying the gene expression of the Sulfolobus spindle-shaped virus 1 (SSV1) in Sulfolobus solfataricus lysogenic cells, a novel viral transcript (Tlys) was identified. Transcriptional analysis revealed that Tlys 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 (T6 and Tind) 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 T5, T6, and Tind 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 T5 and T6, and an apparent cooperativity in binding was observed with the Tind 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.

AB - While studying the gene expression of the Sulfolobus spindle-shaped virus 1 (SSV1) in Sulfolobus solfataricus lysogenic cells, a novel viral transcript (Tlys) was identified. Transcriptional analysis revealed that Tlys 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 (T6 and Tind) 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 T5, T6, and Tind 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 T5 and T6, and an apparent cooperativity in binding was observed with the Tind 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.

U2 - 10.1128/JVI.00458-13

DO - 10.1128/JVI.00458-13

M3 - Journal article

C2 - 23514883

VL - 87

SP - 5926

EP - 5936

JO - Journal of Virology

JF - Journal of Virology

SN - 0022-538X

IS - 10

ER -