Poster: Regulation of gene expression

Abs # 752: Cloning and Expression Analysis of the Third Hemoglobin from Soybean

Presenter:	Kim, Hyo Jeong , khoyjeong@yahoo.co.kr
Authors	Kim, Hyo Jeong  (A)   Lee, Hyoung seok  (A)   An, Chung Sun  (A)
Affiliations:	(A): Seoul National University

Hemoglobins (Hbs) are heme proteins encountered in all five kingdoms of living organisms. In plants, three different classes of Hbs have been identified: nonsymbiotic Hbs from both monocot and dicot species, symbiotic Hbs from nitrogen-fixing plants and so-called 2-on-2 Hbs. This work reports the cloning and analysis of 2-on-2 Hb gene (GmGLB3) from soybean. The GmGLB3 cDNA clone encodes a protein for 172 amino-acid residues, with a molecular weight of 19.8 kDa and a calculated pI value of 7.16. Multiple sequence alignment and phylogenetic analysis have shown high homology with previously reported plant 2-on-2 Hbs and characteristics of them. Northern hybridization shows that the GmGLB3 gene is specifically expressed in root nodules, with levels increasing in the late stage of during nodule development. Also, its transcript level is increased under flooding and kinetin treatment in the root, under flooding and 2-ip treatment in the stem, however no transcript is detected in the leaf under any treatment. Taken together with these results, we propose that GmGLB3 gene is regulated by developmental cues during nodule development and by hormone or other environmental stresses. in situ hybridization will be disdussed here to determine the subcellular localization of three hemoglobins in nodule.