ATHB-5 Antibody

Biological Role of ATHB-5

ATHB-5 is a transcriptional activator that enhances ABA sensitivity, particularly during seed germination and hypocotyl elongation . It directly binds to promoters of target genes such as EXPA3 (a cell wall-loosening enzyme), linking ABA signaling to growth plasticity .

Chromatin Immunoprecipitation (ChIP)

In a landmark study, the ATHB-5 antibody was used to demonstrate in vivo binding of ATHB-5 to the EXPA3 promoter via ChIP-qRT-PCR :

Table 2: ChIP-qRT-PCR Results for ATHB-5–EXPA3 Interaction

Key Insight: ATHB-5 overexpression (OX) significantly enriches EXPA3 promoter binding, confirming its regulatory role in ABA-mediated hypocotyl elongation .

Functional Studies

• ABA Inhibition: ATHB-5 mediates ABA’s suppression of hypocotyl growth during seedling establishment .

• Tissue Localization: Highest expression in hypocotyls and root tips under ABA treatment .

Validation and Quality Control

• Western Blot: A single band at ~35 kDa in Arabidopsis protein extracts .

• Species Specificity: No cross-reactivity with mammalian HD-Zip proteins .

Limitations and Future Directions

• Limited Cross-Species Data: Homology studies are confined to Brassicaceae .

• Structural Data: No co-crystal structures of ATHB-5–antibody complexes are available .