Reference "Four rice genes encoding cysteine synthase: isolation and differential responses to sulfur, nitrogen and light"

Reference ID

3073

Title

Four rice genes encoding cysteine synthase: isolation and differential responses to sulfur, nitrogen and light

Source

Gene, 1999, vol. 229, pp. 155-161

Authors (3)

Nakamura-T	Yamaguchi-Y
Sano-H

Abstract

Four cDNA clones, rcs1, rcs2, rcs3 and rcs4, encoding cysteine synthase [O-
acetylserine(thiol)lyase] were isolated from rice. The predicted amino acid
sequences contain the conserved PXXSVKDR region characteristic of cysteine
synthase, which includes the lysine residue that binds the cofactor, pyridoxal
5'-phosphate. Molecular phylogenic analysis suggests that, whereas rcs1 and rcs3
belong to the cytosolic isoform family, rcs2 and rcs4 form a new family of
cysteine synthase. Transcript accumulation of each gene was examined for organ
specificity, and also for response to sulfur, nitrogen and light. The rcs1
transcript accumulated in all organs examined, and was induced in shoots and
roots upon sulfur starvation under non-limiting nitrogen conditions. The rcs2
transcript accumulated in shoots grown in the light, but disappeared almost
completely by dark treatment. The rcs3 transcript was found more abundantly in
roots than in shoots, and was reduced in the dark, as well as under sulfur and
nitrogen deprivation. The rcs4 transcript was scarce in all organs examined.
These observations indicate that cysteine synthase genes encode functionally
distinct cysteine synthase isoforms, and that they are coordinately regulated by
the availability of sulfur, nitrogen, and light.