InterPro-to-GO mappings (IPR003340 B3 DNA-binding domain; IPR044800 LEC2-like) assign DNA binding and DNA-binding transcription factor activity to VP1, consistent with its experimentally supported role as a B3-domain transcriptional regulator.

UniProt subcellular-location mapping assigns Nucleus and Cytoplasm to VP1; the nucleus is the functionally relevant compartment for this transcription factor, whereas no direct localization experiment for maize VP1 was found in the literature.

Logical inference from the DNA-binding transcription factor activity MF assigns the broad "regulation of DNA-templated transcription" process; VP1's specific role is better captured by positive regulation of RNA Pol II transcription.

SwissProt keyword-derived (SPKW) annotation present in the Sept 2025 goa_uniprot_gcrp snapshot but removed from the current GOA release after GOA retired the keyword2GO pipeline for cellular organisms.

For VP1, the keyword "Abscisic acid signaling pathway" mapped to GO:0009738 (the perception-to-transduction cascade); VP1 is a downstream transcriptional effector that regulates/potentiates ABA responses rather than a component of the core cascade, so the term is better replaced by regulation-of/response-to ABA terms.

VP1 is a B3-domain transcriptional regulator essential for the seed maturation program (desiccation tolerance, dormancy) and for ABA-responsive transcription during embryogenesis; it is the maize ortholog of Arabidopsis ABI3.

VP1 is a modular transcription factor acting as an ABA-dependent co-activator of seed maturation genes via G-box/ABRE elements, a direct B3-dependent sequence-specific activator of C1 via the Sph element, and a repressor of germination-associated genes (alpha-amylase) in aleurone.

vp1 mutants are ABA-insensitive and viviparous (precocious germination, loss of desiccation tolerance); maize VP1 complements Arabidopsis abi3-6, restoring green-seed/desiccation phenotypes and ABA sensitivity of germination.

Multi-omics analysis classifies vp1 as a plant-specific transcription factor acting in ABA signaling and places VP1 at the downstream ABI3 node of the PYL-ABI1-SnRK2-ABI3 core module, downstream of ABA perception/transduction.

VP1 is required for normal developmental ABA responsiveness of rab28; rab28 transcripts fail to accumulate in vp1 embryos despite near-normal ABA levels, though exogenous ABA can partially induce rab28 in young vp1 embryos.

No direct experimental subcellular-localization assay for maize VP1 was found; the report supports a nucleus-consistent function for the DNA-binding transcriptional regulator.

The maize Vp1 gene is specifically required for expression of the maturation program in seed development and encodes a 73,335 Da protein; an acidic transcriptional activation sequence was identified by fusion to the GAL4 DNA-binding domain.

Expression of VP1 in maize protoplasts strongly activated (>130-fold) a reporter gene fused to the promoter of a presumptive target gene, and the acidic domain was essential and replaceable by the HSV VP16 activator; VP1 is a novel transcription factor possibly involved in potentiation of a seed-specific hormone (ABA) response.

35S-driven maize VP1 partially complements the Arabidopsis abi3-6 deletion allele - producing near-wild-type seed, fully restoring ABA sensitivity during seed germination, and suppressing the abi3 early-flowering phenotype - demonstrating functional orthology of VP1 with ABI3 as a seed-maturation regulator.

VP1/ABI3 activation functions are only partially complemented (CRC and C1-GUS activation are markedly lower than wild type), and ectopic VP1 confers a novel ABA-auxin interaction in roots, consistent with VP1 acting as a modular transcriptional regulator.

In the ABA-insensitive vp1 mutant, rab28 transcripts fail to accumulate to a significant level during embryogenesis, showing VP1 is required for normal developmental ABA-responsive expression of the LEA-like rab28 gene.

rab28 mRNA is ABA-inducible in embryos and young leaves, and its proximal promoter contains the conserved ABA-response element CACGTGG; exogenous ABA can partially induce rab28 in young vp1 embryos, indicating stage-dependent partial bypass of VP1.

ZmABI19, a B3-domain transcription factor, directly binds and regulates Viviparous1 in the embryo as part of a grain-filling/seed-development regulatory network, placing VP1 within an ABA-coupled transcriptional circuit.

Both vp1 and vp4 encode a plant-specific transcription factor involved in ABA signaling that can complement the Arabidopsis abi3 mutant allele; multi-omics analysis of vivipary mutants found the ABA core signaling components (PYL-ABI1-SnRK2-ABI3) were affected, placing VP1 at the downstream ABI3 node rather than in ABA perception.