ABCI20 Antibody

Definition and Target

ABCI20 Antibody is a polyclonal antibody raised against the ABCI20 protein, a member of the ATP-binding cassette I (ABCI) subfamily in Arabidopsis. ABCI20 (UniProt ID: Q9LZ98) is a non-intrinsic ABC protein localized to the endoplasmic reticulum (ER) membrane . Unlike classical ABC transporters, ABCI proteins lack transmembrane domains but participate in diverse cellular functions, including cytokinin response modulation .

Functional Role in Cytokinin Signaling

ABCI20, alongside ABCI19 and ABCI21, forms a protein complex that fine-tunes cytokinin responses during early seedling development . Key findings include:

• Hypersensitivity to Cytokinin: Double (abci20 abci21) and triple (abci19 abci20 abci21) knockout mutants exhibited exaggerated growth retardation under cytokinin treatment, suggesting ABCI20 mitigates cytokinin-driven inhibition .

• Tissue-Specific Expression: ABCI20 is expressed in roots and shoots of young seedlings, with light-dependent induction regulated by the transcription factor HY5 .

• ER Localization: ABCI20 interacts with ABCI19 and ABCI21 at the ER membrane, implicating the ER in cytokinin signaling modulation .

Genetic and Molecular Insights

Antibody Development and Validation

The ABCI20 antibody was generated using a synthetic peptide antigen (RTEESRVTGDPARMLN, corresponding to residues 311–326 of ABCI20) . Validation steps included:

• Specificity Testing: Western blotting confirmed a single band at the expected molecular weight (~70 kDa) in wild-type Arabidopsis lysates, absent in knockout lines .

• Immunolocalization: Subcellular localization studies using immunofluorescence linked ABCI20 to the ER .

• Cross-Reactivity: No cross-reactivity with other ABCI family members (e.g., ABCI19 or ABCI21) .

Applications in Research

The ABCI20 antibody has been utilized in:

1. Western Blotting: Detects ABCI20 in plant lysates .

2. Immunoprecipitation: Identifies protein-protein interactions within the ABCI19/20/21 complex .

3. Immunohistochemistry: Visualizes tissue-specific expression patterns in roots and shoots .

Key Insights and Future Directions

ABCI20 is critical for balancing cytokinin activity during seedling development, with its antibody serving as a vital tool for unraveling plant hormone signaling mechanisms. Future studies could explore:

• The molecular mechanism of ABCI20-cytokinin interplay at the ER.

• Broader roles in stress responses or development beyond seedlings.