Epsilon

Gene Description

Helper-phage derepression protein gpEpsilon (95 aa, 10.9 kDa) is encoded in the early essential region of satellite bacteriophage P4. During infection of Escherichia coli lysogenic for helper phage P2, gpEpsilon inactivates the P2 immunity repressor C to derepress the resident helper prophage and activate helper viral transcription and morphogenetic gene expression.

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0050434 positive regulation of viral transcription	IMP PMID:6095206 Nucleotide sequence of the essential region of bacteriophage...	NEW	Summary: Genetic identification of the P4 epsilon gene (epsilon am104) required for derepression of helper prophage P2 transcription. Reason: Amber mutations in the P4 epsilon gene (epsilon am104) abolish the ability of satellite phage P4 to derepress a resident P2 prophage and activate helper phage gene expression. Supporting Evidence: PMID:6095206 The epsilon gene likely encodes a 10 kd protein with epsilon am104 being located at the beginning of the gene.
GO:0019046 release from viral latency	IMP PMID:6095206 Nucleotide sequence of the essential region of bacteriophage...	NEW	Summary: Genetic identification of the P4 epsilon gene required for derepression (induction) of the resident helper prophage P2. Reason: Epsilon is required for derepression (prophage induction) of the P2 helper prophage by satellite phage P4. Supporting Evidence: file:BPP4/Epsilon/Epsilon-uniprot.txt Required for derepression (induction) of the P2 prophage helper by P4.
GO:0140110 transcription regulator activity	IMP PMID:6095206 Nucleotide sequence of the essential region of bacteriophage...	NEW	Summary: Epsilon acts as a transcriptional regulator that counteracts the P2 immunity repressor C to derepress helper prophage transcription. Reason: Genetic and functional analysis shows that P4 gpEpsilon counteracts the P2 immunity repressor C to derepress P2 early transcription. Supporting Evidence: file:BPP4/Epsilon/Epsilon-uniprot.txt Required for derepression (induction) of the P2 prophage helper by P4.

Core Functions

Derepresses resident helper prophage P2 in Escherichia coli by counteracting the P2 immunity repressor, thereby inducing release from viral latency and positively regulating helper viral transcription required for satellite phage P4 propagation.

Molecular Function:

transcription regulator activity

Directly Involved In:

release from viral latency positive regulation of viral transcription

Supporting Evidence:

PMID:6095206
The epsilon gene likely encodes a 10 kd protein with epsilon am104 being located at the beginning of the gene.
file:BPP4/Epsilon/Epsilon-uniprot.txt
Required for derepression (induction) of the P2 prophage helper by P4.

References

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Suggested Experiments

Experiment: Solve the crystal or cryo-EM structure of the P4 gpEpsilon-P2 C repressor heterocomplex and measure operator DNA binding affinity by fluorescence anisotropy.

Hypothesis: gpEpsilon binds the dimerization interface of P2 repressor C, disrupting the relative orientation of its N-terminal helix-turn-helix DNA-binding domains.

Gene Description

Existing Annotations Review

Core Functions

Derepresses resident helper prophage P2 in Escherichia coli by counteracting the P2 immunity repressor, thereby inducing release from viral latency and positively regulating helper viral transcription required for satellite phage P4 propagation.

References

Suggested Questions for Experts

Suggested Experiments

📚 Additional Documentation

Notes

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