Assessment of Fatty Acid Desaturase (Fads2) Structure-Function Properties in Fish in the Context of Environmental adaptations and as a Target for Genetic Engineering

Abstract

Fatty acid desaturase 2 (Fads2) is the key enzyme of long chain polyunsaturated fatty acid (LC-PUFA) biosynthesis. Endogenous production of these biomolecules in vertebrates, if present, is insufficient to meet demand. Hence, LC-PUFA are considered as conditionally-essential. At present however, LC-PUFA are globally-limited nutrients due to anthropogenic factors. Attention of research is given therefore to find ways to maximize endogenous LC-PUFA production especially in production species, whereby deeper knowledge on molecular mechanisms of enzymatic steps involved is being generated. This review first briefly informs about the milestones in the history of LC-PUFA essentiality exploration before it focuses on the main aim – to highlight the fascinating Fads2 potential to play roles fundamental to adaptation to novel environmental conditions. Investigations are summarized, which elucidate the evolutionary history of fish Fads2 providing an explanation for the remarkable plasticity of this enzyme in fish. Further, structural implications of Fads2 substrate specificity are discussed and some relevant studies performed on organisms other than fish are mentioned in cases when such studies have so far not been conducted on fish models. The importance of Fads2 in the context of growing aquaculture demand and dwindling LC-PUFA supply is depicted and a few remedies in the form of genetic engineering to improve endogenous production of these biomolecules are outlined.

Novel polymorphisms in Stearoyl‐CoA Desaturase (SCD) and Fatty Acid Desaturase 2 (FADS2) in channel catfish ( Ictalurus punctatus, Rafinesque, 1818 )

“…Specifically, in the biosynthesis of LC‐PUFA this enzyme converts dietary obtained linoleic acid (18:2n‐6) and Alpha‐linoleic acid (18:3n‐3) into gamma‐linoleic acid and stearidonic acid, respectively. Successively, in the biosynthesis of LC‐PUFAs of omega‐3, it converts tetracosapentaenoic acid into tetracosahexaenoic acid which is then converted to docosahexanoic acid (Bláhová et al., 2020). Similarly to SCD, a few studies have documented the association of genetic variation on fatty acid phenoptypes.…”

“…The FADS2 gene codes for a protein also bound to the endoplasmic reticulum membrane that acts as the first enzyme in the biosynthesis of LC‐PUFA (Bláhová et al., 2020). Specifically, in the biosynthesis of LC‐PUFA this enzyme converts dietary obtained linoleic acid (18:2n‐6) and Alpha‐linoleic acid (18:3n‐3) into gamma‐linoleic acid and stearidonic acid, respectively.…”

“…Recently Suarez‐Salgado et al (2020) explored candidate gene approach and reported novel variations in growth trait related genes in Mexico, but not assessment on meat quality traits are available to date. Two fundamental genes involved in the fatty acid metabolic processes of long chain fatty‐acid biosynthesis are Stearoyl Co‐Desaturase and Fatty Acid Desaturase 2 that have key participation at first stages of the biosynthesis for polyunsaturated fatty acids (Bláhová et al., 2020; Evans et al., 2008) designating them as candidate genes for unrevealing genomic variations and eventually quantitative trait nucleotides. Then the objectives of the present study were the resequencing and discovering of novel variations of these genes in channel catfish.…”