HOS15 Antibody

HOS15: A Transcriptional Corepressor and Stress-Responsive Protein

HOS15 (High Expression of Osmotically Responsive Genes 15) is a nuclear-localized WD40-repeat protein that regulates gene expression through chromatin remodeling and protein degradation. Key roles include:

• Corepressor Activity: HOS15 interacts with histone deacetylases (HDACs) like HD2C and HDA9 to deacetylate histones, repressing stress-responsive genes (e.g., RD29A, COR genes) under non-stressed conditions .

• Immunity Regulation: HOS15 destabilizes NPR1, a master regulator of salicylic acid (SA)-mediated immunity, via SCF/CUL1 E3 ubiquitin ligase complexes. This limits defense gene overexpression and balances growth-defense trade-offs .

• Cold Stress Response: HOS15 promotes HD2C degradation under cold stress, enhancing histone acetylation at cold-responsive gene promoters to activate transcription .

Functional Interactions and Complex Formation

HOS15 operates in dynamic complexes with other proteins and enzymes:

Chromatin-Dependent Repression

• Histone Deacetylation: HOS15 recruits HDACs to repress RD29A and SNC1 (NLR gene) by reducing H4K16ac and H3K9ac levels .

• Epigenetic Regulation: Mutations in hos15 result in hyperacetylated chromatin at stress-responsive promoters, leading to constitutive gene activation .

Protein Degradation Pathways

• SCF/CUL1-Mediated Ubiquitination: HOS15 acts as a substrate receptor for SCF/CUL1 E3 ligases, tagging NPR1 for proteasomal degradation .

• Cold-Induced HD2C Degradation: HOS15 facilitates HD2C turnover under cold stress, enabling CBF transcription factors to activate cold-responsive genes .

Phenotypic and Physiological Impacts

Research Gaps and Future Directions

1. Antibody-Specific Studies: No studies directly address HOS15-specific antibodies. Antibodies targeting HOS15 may be used in immunoblotting or immunoprecipitation to study its subcellular localization or interactions.

2. Cross-Talk with Other Pathways: HOS15’s role in integrating SA, ABA, and cold signaling warrants further investigation .

3. Agricultural Applications: hos15 mutants show enlarged siliques and enhanced stress tolerance, suggesting breeding potential .