The S-adenosyl-L-homocysteine hydrolase of Drosophila melanogaster: identification, deduced amino acid sequence and cytological localization of the structural gene.
S-adenosyl-L-homocysteine hydrolase (AdoHcyase, EC 3.3.1.1) catalyzes the hydrolysis of S-adeno-syl-L-homocysteine to adenosine and homocysteine and thus plays a crucial role in normal cellular metabolism. We have isolated the cDNA for Drosophila melanogaster AdoHcyase by screening a Drosophila ovarian expression library. The 1584-nucleotide cDNA encodes a protein of 431 amino acids, showing 80.5% identity with human AdoHcyase. Southern analysis of genomic DNA and in situ hybridization to salivary gland chromosomes indicate that a single gene encodes the D. melanogaster AdoHcyase. The gene resides in region 13C1-2 on the X chromosome. Transcript analysis shows a single AdoHcyase mRNA present in unfertilized eggs, and, at a more or less constant level of expression, in all developmental stages tested, ranging from early embryos to adults. The deduced amino acid sequence was compared to a putative AdoHcyase-like protein encoded by a cDNA mapping to the 89E region of the second chromosome and showing much lower similarity to known AdoHcyases. We discuss the hypothesis that a sequence that originated by duplication of an ancestral AdoHcyase gene has, in the course of evolution, been recruited to supply a different function.
Caggese
C
C
Istituto di Genetica, Università di Bari, Italy.
Ragone
G
G
Barsanti
P
P
Moschetti
R
R
Messina
A
A
Massari
S
S
Caizzi
R
R
D043383:Adenosylhomocysteinase; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004331:Drosophila melanogaster / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006867:Hydrolases / Q000737:chemistry* / Q000235:genetics*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014960:X Chromosome
D018076:DNA, Complementary; D012333:RNA, Messenger; D006867:Hydrolases; D043383:Adenosylhomocysteinase