Ontogenic Expression And Characterization Of The Longchained Polyunsaturated Fatty Acid Biosynthesis Enzyme, Elongase In Zebrafish
Loading...
Date
2012
Authors
Tan, Sze Huey
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The importance of long-chained polyunsaturated fatty acids (LC-PUFAs) in
vertebrates’ development has been widely studied. Among these, include roles in
maintaining cellular membrane integrity, cellular signaling, gene regulation and
metabolism. LC-PUFAs such as arachidonic acid, eicosapentaenoic acid and
docosahexaenoic acid also mediate physiological processes like inflammation,
immunity, reproduction and development. Despite the known importance of LCPUFAs
during development, very little is known about their utilization and
biosynthesis during embryogenesis. Zebrafish embryos possess distinct advantages
as model organism in developmental biology, including the ease of visualization, the
availability of large numbers of offspring coupled with the existing molecular
methods and tools. LC-PUFAs are synthesized via alternating desaturation and
elongation steps with the key enzymes: desaturase and elongase. This present study
describes the expression and functional characterization of two family members of
elongases, elovl5 and elovl2 in zebrafish embryogenesis. elovl5 is significantly
expressed at highest level at initial embryogenic stage which imply the maternal
transfer process. Conversely, elovl2 is expressed at low level at initial stage and
gradually elevated as embryo developed. Spatially, both elovl5 and elovl2 are found
expressed in brain as early as 24hpf. However, as the embryos develop, they
displayed distinct spatial expression. elovl5 is specifically expressed in pronephric
tubules and yolk syncytial layer while elovl2 predominantly expressed in liver and
intestine. In addition, profiling of fatty acids shows a general decrement of the
substrates and increase of the LC-PUFAs as the embryo develops, which match the
increasing expression of both elongases. Functional characterization of both genes
was elucidated using knockdown approach. Knockdown of elovl5 and elovl2,
respectively produced microcephaly embryos at early embryonic stage and
eventually pericardial and yolk sac edema developed. In elovl5 knockdown, there
seems to be no effect on pronephric development as intact segmentation of the
pronephric tubules in morphants was confirmed by in situ hybridization using
corresponding markers.
Description
Keywords
The longchained polyunsaturated fatty acid , biosynthesis enzyme, elongase in zebrafish