Abstract: At3g23140 is a transcription factor with one single C2H2 zinc finger domain, containing C2H2 zinc finger domain in Nterminal regions and a Cterminal EARmotiflike sequence. Two different fragments of 〖WTBX〗〖STBX〗At3g23140〖STB3〗〖WTBZ〗 that only contain the C2H2type zincfinger domain were inserted downstream of 35S promoter in the plant expression vector pMON530, and introduced into wildtype Landsberg erecta (Ler). Independent homozygous transgenic lines were obtained after selection of T3 progenies. Ethylene detection results showed that endogenous ethylene value of 35S::〖WTBX〗〖STBX〗 A2〖STB3〗〖WTBZ〗 transgenic plants was less than that of the control, which was consistent with the phenotype of〖WTBX〗〖STBX〗 cs16966〖STB3〗〖WTBZ〗, but endogenous ethylene value of transgenic plant 35S::〖WTBX〗〖STBX〗 A1〖STB3〗〖WTBZ〗 has no significant difference with that of the wildtype. It indicated that repression was caused by overexpression of A2, which may due to A2 competing for the DNA sequence regulated by 〖WTBX〗〖STBX〗At3g23140〖STB3〗〖WTBZ〗, and nonC2H2 zinc finger domain of the Cterminal regions of A2 is essential for At3g23140 integrating with targeted DNA.

Key words: zinc finger protein, transcription factor, competition , Arabidopsis thaliana, zinc finger protein, transcription factor, competition