Biopolymers and cell. 2005; 21 (3): 187 - 219

Genetic and epigenetic control of plant growth and development. Molecular-genetic control of transmission and realization of auxin signals

V. A. Tsygankova, L. A. Galkina, L. I. Musatenko, K. M. Sytnik

In the review the data on regulator components of the indole-3-acetic acid (IAA) signal pathway in plant cells are presented: the membrane proteins-receptors perceiving the exogenous signals of IAA, the system of second messengers (cAMP, cGMP, inosytoltriphosphat and diacylglycerol, cytoplasmic calcium, the «sensory» protein of the Ca²⁺ signals - kalmodulin), which mediate transmission of the IAA signals from receptors to effectors (enzymes), catalyzing processes of intracellular metabolism. The list of recently identified genes, which determine the synthesis of proteins participating in transmission of the IAA signals at Arabidopsis, is given: the gene ABP1, encoding membrane protein - the IAA receptor; the AtCP1 and AtCBL1 genes, encoding «sensory» proteins of Ca²⁺; numerous families of the MDR genes of membrane proteins participating in the active-dependent transport of the proton form IAA through the cell membranes, the PIN genes of proteins, controlling passive polar intra- and intercellular transport of anionic form of the IAA, ARG1 and RCN genes of proteins responsible for the transmission of gravitropic signals and regulating the polar transport of the anionic form IAA through the membranes of the specialized gravity-perceiving cells - statocytes, the VTI genes of the SNAREs proteins participating in the vesicular intracellular transport IAA, and the AtMRP5 gene of protein - transporter of the conjugated forms of IAA; the ARF genes of auxin-activated transfactors, controlling expression of early auxin-regulated Aux/IAA, SAUR, CH3 genes, and also the numerous families of the SKP1, RBX1, ATCUL1, ASK1, ASK2, AXR1, ECR1, RCE1, ENR2p, Cdc4p, Cdc53p, Scp1p, TIR1 genes of proteins (members of ubiquitin-protein ligases complex) and CSN genes of proteins (members of multisubunit protein regulator complex of COP9 signalosome) - components of ubiquitin/proteasomemediated degradation of Aux/IAA proteins repressing transmission of auxin signals. The hypothetical model of regulation of genes expression by the IAA is considered.

Key words: the indole-3-acetic acid (IAA) receptors, second messendgers of IAA, proteins-transporters of IAA, auxin-regulated genes, ubiquitin-proteasome's way degradation of proteins-repressors of IAA.