title: Delta-9 fatty acid desaturase gene containing a carboxyl-terminal cytochrome b5 domain from the red alga Cyanidioschyzon merolae.
abstract: A delta-9 fatty acid desaturase gene, homologous to animal and fungal acyl-coenzyme A (CoA) desaturases, was isolated from the red alga Cyanidioschyzon merolae using a degenerate PCR strategy. This gene, designated as CmFAD9, has no intron. The encoded delta-9 fatty acid desaturase (CmFad9p) consists of 476 amino acids and has an estimated molecular mass of 55.4 kDa. CmFad9p is a unique delta-9 fatty acid desaturase among plants, in that it is fused with the cytochrome b5 domain at its carboxyl terminus. This is characteristic of yeast acyl-CoA desaturase. Genomic Southern hybridization suggested that the C. merolae genome contains a single gene for delta-9 fatty acid desaturase of the animal and fungal type. Southern hybridization combined with pulsed-field gel electrophoresis revealed that CmFAD9 is probably located on chromosome XI of the 17 C. merolae chromosomes. A 1.6-kb product of this gene was transcribed throughout a light/dark synchronization culture. The discovery of CmFAD9 indicates the existence of a novel type of plant delta-9 fatty acid desaturase that may function in the endoplasmic reticulum, but not in the plastid.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan. rgitoh@biol.s.u-tokyo.ac.jp
authors.forename: R
authors.initials: R
authors.lastname: Itoh
authors.forename: K
authors.initials: K
authors.lastname: Toda
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Takano
authors.forename: T
authors.initials: T
authors.lastname: Kuroiwa
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D015786:Cytochromes b5 / Q000235:genetics*; D019143:Evolution, Molecular; D044943:Fatty Acid Desaturases / Q000235:genetics*; D018628:Gene Dosage; D005786:Gene Expression Regulation / Q000528:radiation effects; D005796:Genes / Q000235:genetics*; D008969:Molecular Sequence Data; D017440:Photoperiod; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D000461:Rhodophyta / Q000201:enzymology / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013230:Stearoyl-CoA Desaturase
chemical_list: D012333:RNA, Messenger; D015786:Cytochromes b5; D044943:Fatty Acid Desaturases; D013230:Stearoyl-CoA Desaturase; C029627:delta-9 fatty acid desaturase