Cm. Chow et Ul. Rajbhandary, DEVELOPMENTAL REGULATION OF THE GENE FOR FORMATE DEHYDROGENASE IN NEUROSPORA-CRASSA, Journal of bacteriology, 175(12), 1993, pp. 3703-3709
We have isolated and characterized a gene,fdh, from Neurospora crassa
which is developmentally regulated and which produces formate dehydrog
enase activity when expressed in Escherichia coli. The gene is closely
linked (less than 0.6 kb apart) to the ku-5 gene encoding mitochondri
al leucyl-tRNA synthetase; the two genes are transcribed convergently
from opposite strands. The expression patterns of these genes differ:f
dh mRNA is found only during conidiation and early germination and is
not detectable during mycelial growth, while ku-5 mRNA appears during
germination and mycelial growth. The structure of the fdh gene was det
ermined from the sequence of cDNA and genomic DNA clones and from mRNA
mapping studies. The gene encodes a 375-amino-acid-long protein with
sequence similarity to NAD-dependent dehydrogenases of the E. coli 3-p
hosphoglycerate dehydrogenase (serA gene product) subfamily. In partic
ular, there is striking sequence similarity (52% identity) to formate
dehydrogenase from Pseudomonas sp. strain 101. All of the residues tho
ught to interact with NAD in the crystal structure of the Pseudomonas
enzyme are conserved in the N. crassa enzyme. We have further shown th
at expression of the N. crassa gene in E. coli leads to the production
of formate dehydrogenase activity, indicating that the N. crassa gene
specifies a functional polypeptide.