Open AccessAmphioxus alcohol dehydrogenase is a class 3 form of single type and of structural conservation but with unique developmental expression
Author(s) -
Cañestro Cristian,
Hjelmqvist Lars,
Albalat Ricard,
GarciaFernàndez Jordi,
GonzàlezDuarte Roser,
Jörnvall Hans
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01711.x
Subject(s) - biology , alcohol dehydrogenase , vertebrate , neurula , northern blot , gene , formaldehyde dehydrogenase , genetics , enzyme , gene expression , microbiology and biotechnology , biochemistry , glutathione , embryogenesis , gastrulation
The coding region of amphioxus alcohol dehydrogenase class 3 (ADH3) has been characterized from two species, Branchiostoma lanceolatum and Branchiostoma floridae . The species variants have residue differences at positions that result in only marginal functional distinctions. Activity measurements show a class 3 glutathione‐dependent formaldehyde dehydrogenase, with k cat / K m values about threefold those of the human class 3 ADH enzyme. Only a single ADH3 form is identified in each of the two amphioxus species, and no ethanol activity ascribed to other classes is detectable, supporting the conclusion that evolution of ethanol‐active ADH classes by gene duplications occurred at early vertebrate radiation after the formation of the amphioxus lineage. Similarly, Southern blot analysis indicated that amphioxus ADH3 is encoded by a single gene present in the methylated fraction of the amphioxus genome and northern blots revealed a single 1.4‐kb transcript. In situ experiments showed that amphioxus Adh3 expression is restricted to particular cell types in the embryos. Transcripts were first evident at the neurula stage and then located at the larval ventral region, in the intestinal epithelium. This tissue‐specific pattern contrasts with the ubiquitous Adh3 expression in mammals.