[LAH-3, a transcriptional factor involved in osmotic regulation in Neurospora crassa]

[OBJECTIVE] In order to identify the function of lah-3 in osmotic regulation, we generated lah-3 deletion strain and analyzed its phenotype by osmostress treatment. [METHODS] We used homologous recombination to replace lah-3gene by hph gene and treated these cells with 4% NaCl and 1 M sorbitol to analyze the phenotype. Northern blot was used to detect the expressions of osmoresponsing genes. Western blot was used to examine the phosphorylation level of LAH-3 and OS-2 and the expression of OS-2. [RESULTS] In the deletion strain of transcription factor lah-3 gene, the expressions of osmoresponsing genes gcy-1, stl-1 and pck-1 were significantly reduced. Besides, the phosphorylation level of LAH-3 protein increased under the osmostress treatment. The phosphorylation of LAH-3 was not mediated by OS-2. The deletion of lah-3 did not affect the os-2 expression and the phosphorylation level of OS-2 upon osmostress. [ CONCLUSION] LAH-3 involved in osmoresponsing was independent of OS-2 MAPK pathway.