Developmental regulation of nodule-specific genes in alfalfa root nodules.
We have cloned alfalfa nodule-specific cDNAs that code for leghemoglobin (Lb), glutamine synthetase (GS), and three unidentified nodulins. Hybrid-select translation of nodule RNA followed by 2-D gel electrophoresis showed that the Lb-specific cDNA corresponded to at least four Lb species of 12 kDa. One of the unidentified cDNA clones (N-32/34) corresponded to at least five polypeptides of 32-34 kDa; a second unidentified cDNA clone (N-14) corresponded to an individual polypeptide of 14 kDa. The in vitro translation product(s) of the RNA hybrid selected by the third unidentified cDNA clone (N-22) formed a single band at 22 kDa on a one-dimensional gel. Northern and dot blot analyses of RNA isolated from wild-type nodules and from defective nodules elicited by a variety of Rhizobium meliloti mutants showed that 1) RNAs corresponding to the Lb, nodule-specific GS, and three unidentified nodulins were coordinately expressed during the course of nodule development, and 2) all five nodulins were expressed in Fix- nodules that contained infection threads and bacteroids but were not expressed in nodules that lacked infection threads and intracellular rhizobia.
Dunn
K
K
Department of Genetics, Harvard Medical School, Boston 02114.
Dickstein
R
R
Feinbaum
R
R
Burnett
B K
BK
Peterman
T K
TK
Thoidis
G
G
Goodman
H M
HM
Ausubel
F M
FM
D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D005974:Glutamate-Ammonia Ligase / Q000235:genetics*; D007700:Kinetics; D000455:Medicago sativa / Q000235:genetics* / Q000254:growth & development; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D014176:Protein Biosynthesis
D008565:Membrane Proteins; D010940:Plant Proteins; C045625:nodulin; D004247:DNA; D005974:Glutamate-Ammonia Ligase