Recombinant Ictalurid herpesvirus 1 Uncharacterized protein ORF38 (ORF38)
Description
Introduction to ORF38
ORF38 is a gene product of Ictalurid herpesvirus 1 (IcHV1), a pathogen causing severe economic losses in catfish aquaculture. While IcHV1 has been extensively studied due to its impact on the fish industry, ORF38 remains poorly characterized, with limited functional data.
Temporal Expression
| Time Post-Infection | Expression Profile | Kinetic Class |
|---|---|---|
| 1–2 hours | Peak transcription | Early |
| 3–8 hours | Sustained low-level | Early |
| >8 hours | Undetectable | — |
Regulatory Features
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Promoter Analysis: The ORF38 promoter region contains a TATA-like sequence (TATTAA) and a CCAAT box, resembling early herpesvirus promoters .
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Dependence on Viral DNA Synthesis: Unlike immediate-early genes, ORF38 transcription requires de novo viral protein synthesis .
Genomic Organization and Overlap
ORF38 overlaps transcriptionally with ORF39, a late kinetic-class gene encoding the major capsid protein .
Hypothesized Roles
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Regulatory Function: May modulate the transition from early to late gene expression .
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Structural Support: Potential involvement in capsid assembly or viral DNA packaging, inferred from proximity to ORF39 .
Research Gaps
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Protein Localization: No data on subcellular localization or interaction partners.
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Functional Validation: No knockout or knockdown studies to assess ORF38’s necessity in viral replication .
Comparative and Evolutionary Context
ORF38 shows limited homology to proteins in other herpesviruses, suggesting lineage-specific evolution .
Sequence Alignments
| Virus | Homologous ORF | E-value | Functional Prediction |
|---|---|---|---|
| Acipenserid herpesvirus 2 | ORF37 | 1.31E-98 | Hypothetical protein |
| Salmonid herpesvirus 1 | ORF46 | 2.48E-106 | Hypothetical protein |
