ABSTRACT
Previous results revealed that haem oxygenase-1 (HO-1)/carbon monoxide (CO) system is involved in auxin-induced adventitious root formation. In this report, a cDNA for the gene ZmHO-1, encoding an HO-1 protein, was cloned from Zea mays seedlings. ZmHO-1 has a conserved HO signature sequence and shares highest homology with rice SE5 (OsHO-1) protein. We further discovered that N-1-naphthylacetic acid (NAA), haemin, and CO aqueous solution, led to the induction of ZmHO-1 expression as well as the thereafter promotion of lateral root development. These effects were specific for ZmHO-1 since the potent HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) differentially blocked the above actions. The addition of haemin and CO were able to reverse the auxin depletion-triggered inhibition of lateral root formation as well as the decreased ZmHO-1 transcripts. Molecular evidence showed that the haemin- or CO-mediated the modulation of target genes responsible for lateral root formation, including ZmCDK and ZmCKI2, could be blocked by ZnPPIX. Overexpression of ZmHO-1 in transgenic Arabidopsis plants resulted in promotion of lateral root development as well as the modulation of cell cycle regulatory gene expressions. Overall, our results suggested that a maize HO-1 gene is required for the lateral root formation.
Subject(s)
Genes, Plant/genetics , Heme Oxygenase-1/genetics , Plant Proteins/genetics , Plant Roots/enzymology , Plant Roots/growth & development , Zea mays/enzymology , Zea mays/genetics , Arabidopsis/drug effects , Arabidopsis/genetics , Carbon Monoxide/pharmacology , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cloning, Molecular , Down-Regulation/drug effects , Enzyme Inhibitors/pharmacology , Gene Expression Profiling , Gene Expression Regulation, Enzymologic/drug effects , Gene Expression Regulation, Plant/drug effects , Heme Oxygenase-1/metabolism , Hemin/pharmacology , Indoleacetic Acids/pharmacology , Molecular Sequence Data , Naphthaleneacetic Acids/pharmacology , Phenotype , Phylogeny , Plant Proteins/metabolism , Plant Roots/genetics , Plants, Genetically Modified , Protoporphyrins/pharmacology , Seedlings/drug effects , Seedlings/genetics , Seedlings/growth & development , Sequence Analysis, DNA , Zea mays/growth & developmentABSTRACT
OBJECTIVE: To obtain clues for early diagnosis of the tumors in orbital apex and optic nerve. METHODS: Twenty-two cases (22 eyes) of orbital tumors without proptosis were collected, and their clinical manifestations, especially main or first symptoms, the course of their diagnosis and treatment as well as the data of ultrasonography-B, CT and MRI were analyzed. RESULTS: Among 22 cases of the orbital tumors, there were 6 cases of cavernous hemangioma, 6 cases of the tumors from paransal sinuses or nasopharyngeal cavity, 4 cases of neurilemmoma and optic nerve sheath meningioma, neurofibroma, and 1 case of optic nerve glioma. There were 17 cases with visual impairment as the first presenting symptom and 3 cases with visual impairment associated with diplopia which was misdiagnosed as optic neuritis or optic atrophy. Finally, all cases were diagnosed accurately by CT or MRI. The vast majority of that originated from the orbital apex or optic nerve sheath, and the biggest diameter of the tumors was smaller than 1.5 cm. CONCLUSIONS: The early symptoms of the tumors in orbital apex and optic nerve tumors were visual impairment without proptosis. It is important that these patients were examined early by CT and MRI.
