Nuclear localization of a hypoxia-inducible novel non-symbiotic hemoglobinin cultured alfalfa cells

We have isolated a 483-hp-long full-length cDNA clone encoding a non-symbio tic hemoglobin called Mhb1, the first one found in alfalfa. This non-symbio tic hemoglobin is a single copy gene localized in linkage group 4 in diploi d Medicago genome. The Mhb1 mRNA was found only in the roots of alfalfa pla nts. The Mhb1 gene was inducible by hypoxia and showed no induction by cold stress treatment. The Mhb1 transcript level increased at the G2/M boundary in a synchronized alfalfa cell suspension culture, The majority of Mhb1 pr otein was shown to be localized in the nucleus and smaller amounts were det ected in the cytoplasm. A potential link to the nitric oxide signalling pat hway is also discussed, (C) 2000 Federation of European Biochemical Societi es. Published by Elsevier Science B.V. All rights reserved.