Gene identification and functional characterization of a Δ12 fatty acid desaturase in Tetrahymena thermophila and its influence in homeoviscous adaptation to low temperature

Publication date: Available online 14 August 2019Source: Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of LipidsAuthor(s): Maria L. Sanchez Granel, Camila Cánepa, Nicolas G. Cid, Juan C. Navarro, Óscar Monroig, Sandra V. Verstraeten, Clara B. Nudel, Alejandro D. NusblatAbstractHomeoviscous adaptation in poikilotherms is based in the regulation of the level of desaturation of fatty acids, variation in phospholipids head groups and sterol content in the membrane lipids, in order to maintain the membrane fluidity in response to changes in environmental temperature. Increased proportion of unsaturated fatty acids is thought to be the main response to low-temperature acclimation, which is mostly achieved by fatty acid desaturases. Genome analysis of the ciliate Tetrahymena thermophila and a gene knockout approach has allowed us to identify one Δ12 FAD and to study its activity in the original host and in a yeast heterologous expression system. The “PUFA index” -relative content of polyunsaturated fatty acids compared to the sum of saturated and monounsaturated fatty acid content- was ~57% lower at 15 °C and 35 °C in the Δ12 FAD gene knockout strain (KOΔ12) compared to WT strain. We characterized the role of T. thermophila Δ12 FAD on homeoviscous adaptation and analyzed its involvement in cellular growth, cold stress response, and membrane fluidity, as well as its expression pattern during temperature shifts. Although these alterations allowed nor...
Source: Biochimica et Biophysica Acta (BBA) Molecular and Cell Biology of Lipids - Category: Lipidology Source Type: research