AUXIN RESPONSE FACTOR8 regulates Arabidopsis petal growth by interacting with the bHLH transcription factor BIGPETALp.

Plant organ growth and final size are determined by coordinated cell proliferation and expansion. The BIGPETALp (BPEp) basic helix-loop-helix (bHLH) transcription factor was shown to limit Arabidopsis thaliana petal growth by influencing cell expansion. We demonstrate here that BPEp interacts with AUXIN RESPONSE FACTOR8 (ARF8) to affect petal growth.

Recent progress in auxin biology.

Like animals, plants have evolved into complex organisms. Developmental cohesion between tissues and cells is possible due to signaling molecules (messengers) like hormones. The first hormone discovered in plants was auxin.

Conformational dynamics underlie the activity of the auxin-binding protein, Nt-abp1.

The auxin-binding protein 1 (ABP1) has been proposed to be involved in the perception of the phytohormone at the plasma membrane. Site-directed mutagenesis was performed on highly conserved residues at the C terminus of ABP1 to investigate their relative importance in protein folding and activation of a functional response at the plasma membrane. Detailed analysis of the dynamic interaction of the wild-type ABP1 and mutated proteins with three distinct monoclonal antibodies recognizing conformation-dependent epitopes was performed by surface plasmon resonance.

A novel immunological approach establishes that the auxin-binding protein, Nt-abp1, is an element involved in auxin signaling at the plasma membrane.

Interactions of a collection of monoclonal antibodies (mAbs) to the recombinant Nicotiana tabacum auxin-binding protein 1 (Nt-abp1) were extensively characterized using surface plasmon resonance. Dynamic interaction studies using combinations of Nt-abp1, synthetic peptides corresponding to conserved sequences within auxin-binding proteins, and the mAbs have shown that a number of the mAbs recognized discontinuous epitopes revealing the junction of distinct domains in the folded protein. In particular, the two putative auxin binding domains and the C terminus of the protein were shown to interact with each other in the folded protein.

The auxin-binding protein Nt-ERabp1 alone activates an auxin-like transduction pathway.

Hyperpolarization of tobacco protoplasts is amongst the earliest auxin responses described. It has been proposed that the auxin-binding protein, ABP1, or a related protein could be involved in the first step of auxin perception at the plasma membrane. Using for the first time homologous conditions for interaction between the protein Nt-ERabp1 or a synthetic peptide corresponding to the C-terminus and tobacco protoplasts, we have demonstrated that both can induce the hyperpolarization response.

Ethylene-Induced Increase in Glutamine Synthetase Activity and mRNA Levels in Hevea brasiliensis Latex Cells.

Ethylene, used as a stimulant of latex production in Hevea brasiliensis, significantly activates the regenerating metabolism within the laticiferous cells. In this context, attention was focused on glutamine synthetase (GS; EC 6.3.

Detection of phosphoenolpyruvate and ribulose 1,5-bisphosphate carboxylase transcripts in maize leaves by in situ hybridization with sulfonated cDNA probes.

This report outlines an efficient in situ hybridization method for locating specific mRNAs in tissue cryosections using sulfonated cDNA probes. The method involves chemical modification of DNA probes by insertion of a sulfone radical on cytosine residues, which generates a specific epitope. Sulfonated DNA is then detected by using indirect immunochemical procedure.

Phosphoenolpyruvate carboxylase in soybean root nodules: An immunochemical study.

The activity of phosphoenolpyruvate carboxylase (E.C. 4.

In-situ immunofluorescent localization of phosphoenolpyruvate and ribulose 1,5-bisphosphate carboxylases in leaves of C3, C 4, and C 3-C 4 intermediatePanicum species.

The in-situ inter- and intracellular localization patterns of phosphoenolpyruvate (PEP) and ribulose 1,5-bisphosphate (RuBP) carboxylases in green leaves of severalPanicum species were investigated using an indirect immunofluorescence technique. Four species were examined and compared:P. miliaceum (C4),P.

Glutamine Synthetase in Spinach Leaves : IMMUNOLOGICAL STUDIES AND IMMUNOCYTOCHEMICAL LOCALIZATION.

By polyacrylamide gel electrophoresis, DEAE Sephacel, and hydroxyapatite chromatography, one form of glutamine synthetase has been identified in spinach (Spinacia oleracea L. cv. Monstrueux de Viroflay) leaves.

Immunocytochemical study of phosphoenolpyruvate carboxylase in nodulated Alnus glutinosa.

The activities of phosphoenolpyruvate carboxylase (PEP carboxylase, EC 4.1.1.