title: Verification, characterization and tissue-specific expression of UreG, a urease accessory protein gene, from the amphioxus Branchiostoma belcheri.
abstract: UreG genes have been found in bacteria, fungi and plants but have not yet identified in animals, although a putative UreG-like gene has been documented in sea urchin. In the course of a large-scale sequencing of amphioxus gut cDNA library, we have identified a cDNA with high similarity to UreG genes. Both reverse transcription-polymerase chain reaction and nested polymerase chain reaction, as well as in situ hybridization histochemistry, verified that the cDNA represented an amphioxus UreG gene (AmphiUreG) rather than a microbial contaminant of the cDNA library. This is further supported by the presence of urease activity in amphioxus gut, gill and ovary. AmphiUreG encodes a deduced protein of 200 amino acid residues including a highly conserved P-loop, bearing approximately 46%-49%, 44%-48%, and 29%-37% similarity to fungal, plant and bacterial UreG proteins, respectively. It shows a tissue-specific expression pattern in amphioxus, and is especially abundant in the digestive system. This is the first UreG gene identified in animal species.
authors.affiliation: Department of Marine Biology, Ocean University of China, Qingdao 266003, China.
authors.forename: Ji-Yu
authors.initials: JY
authors.lastname: Xue
authors.forename: Shi-Cui
authors.initials: SC
authors.lastname: Zhang
authors.forename: Nai-Guo
authors.initials: NG
authors.lastname: Liu
authors.forename: Zhen-Hui
authors.initials: ZH
authors.lastname: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002816:Chordata, Nonvertebrate / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D016415:Sequence Alignment; D014018:Tissue Distribution; D014510:Urease / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D012333:RNA, Messenger; D014510:Urease