The Use of a Fatty Acid Desaturase Mutant of Saccharomyces cerevisiae to Investigate the Role of Lipids in Mitochondrial Membrane Functions

1974 ◽  
Vol 2 (2) ◽  
pp. 207-209 ◽  
Author(s):  
J. M. HASLAM ◽  
GARY S. COBON ◽  
ANTHONY W. LINNANE
Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1245
Author(s):  
Naoufal Lakhssassi ◽  
Valéria Stefania Lopes-Caitar ◽  
Dounya Knizia ◽  
Mallory A. Cullen ◽  
Oussama Badad ◽  
...  

Soybean is the second largest source of oil worldwide. Developing soybean varieties with high levels of oleic acid is a primary goal of the soybean breeders and industry. Edible oils containing high level of oleic acid and low level of linoleic acid are considered with higher oxidative stability and can be used as a natural antioxidant in food stability. All developed high oleic acid soybeans carry two alleles; GmFAD2-1A and GmFAD2-1B. However, when planted in cold soil, a possible reduction in seed germination was reported when high seed oleic acid derived from GmFAD2-1 alleles were used. Besides the soybean fatty acid desaturase (GmFAD2-1) subfamily, the GmFAD2-2 subfamily is composed of five members, including GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E. Segmental duplication of GmFAD2-1A/GmFAD2-1B, GmFAD2-2A/GmFAD2-2C, GmFAD2-2A/GmFAD2-2D, and GmFAD2-2D/GmFAD2-2C have occurred about 10.65, 27.04, 100.81, and 106.55 Mya, respectively. Using TILLING-by-Sequencing+ technology, we successfully identified 12, 8, 10, 9, and 19 EMS mutants at the GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E genes, respectively. Functional analyses of newly identified mutants revealed unprecedented role of the five GmFAD2-2A, GmFAD2-2B, GmFAD2-2C, GmFAD2-2D, and GmFAD2-2E members in controlling the seed oleic acid content. Most importantly, unlike GmFAD2-1 members, subcellular localization revealed that members of the GmFAD2-2 subfamily showed a cytoplasmic localization, which may suggest the presence of an alternative fatty acid desaturase pathway in soybean for converting oleic acid content without substantially altering the traditional plastidial/ER fatty acid production.


2018 ◽  
Vol 128 ◽  
pp. 21-25 ◽  
Author(s):  
Hui Gyu Park ◽  
Matthew G. Engel ◽  
Kyle Vogt-Lowell ◽  
Peter Lawrence ◽  
Kumar S. Kothapalli ◽  
...  

1991 ◽  
Vol 11 (11) ◽  
pp. 5487-5496 ◽  
Author(s):  
M E Dumont ◽  
T S Cardillo ◽  
M K Hayes ◽  
F Sherman

Heme is covalently attached to cytochrome c by the enzyme cytochrome c heme lyase. To test whether heme attachment is required for import of cytochrome c into mitochondria in vivo, antibodies to cytochrome c have been used to assay the distributions of apo- and holocytochromes c in the cytoplasm and mitochondria from various strains of the yeast Saccharomyces cerevisiae. Strains lacking heme lyase accumulate apocytochrome c in the cytoplasm. Similar cytoplasmic accumulation is observed for an altered apocytochrome c in which serine residues were substituted for the two cysteine residues that normally serve as sites of heme attachment, even in the presence of normal levels of heme lyase. However, detectable amounts of this altered apocytochrome c are also found inside mitochondria. The level of internalized altered apocytochrome c is decreased in a strain that completely lacks heme lyase and is greatly increased in a strain that overexpresses heme lyase. Antibodies recognizing heme lyase were used to demonstrate that the enzyme is found on the outer surface of the inner mitochondrial membrane and is not enriched at sites of contact between the inner and outer mitochondrial membranes. These results suggest that apocytochrome c is transported across the outer mitochondrial membrane by a freely reversible process, binds to heme lyase in the intermembrane space, and is then trapped inside mitochondria by an irreversible conversion to holocytochrome c accompanied by folding to the native conformation. Altered apocytochrome c lacking the ability to have heme covalently attached accumulates in mitochondria only to the extent that it remains bound to heme lyase.


2013 ◽  
Vol 431 (4) ◽  
pp. 675-679 ◽  
Author(s):  
Li-Ying Song ◽  
Wan-Xiang Lu ◽  
Jun Hu ◽  
Wei-Bo Yin ◽  
Yu-Hong Chen ◽  
...  

1998 ◽  
Vol 330 (2) ◽  
pp. 611-614 ◽  
Author(s):  
A. Johnathan NAPIER ◽  
J. Sandra HEY ◽  
J. Dominic LACEY ◽  
R. Peter SHEWRY

We identified a cDNA expressed sequence tag from an animal (the nematode worm Caenorhabditis elegans) that showed weak similarity to a higher-plant microsomal Δ6-desaturase. A full-length cDNA clone was isolated and expressed in the yeast Saccharomyces cerevisiae. This demonstrated that the protein encoded by the C. elegans cDNA was that of a fatty acid Δ6-desaturase, as determined by the accumulation of γ-linolenic acid. The C. elegans Δ6-desaturase contained an N-terminalcytochrome b5 domain, indicating that it had a similar structure to that of the higher-plant Δ6-desaturase. The C. elegans Δ6-desaturase mapped to cosmid W08D2, a region of chromosome III. This is the first example of a Δ6-desaturase isolated from an animal and also the first example of an animal desaturase containing a cytochrome b5 domain.


2007 ◽  
Vol 73 (21) ◽  
pp. 6965-6971 ◽  
Author(s):  
Hisashi Yazawa ◽  
Hitoshi Iwahashi ◽  
Yasushi Kamisaka ◽  
Kazuyoshi Kimura ◽  
Tsunehiro Aki ◽  
...  

ABSTRACT To make dihomo-γ-linolenic acid (DGLA) (20:3n-6) in Saccharomyces cerevisiae, we introduced Kluyveromyces lactis Δ12 fatty acid desaturase, rat Δ6 fatty acid desaturase, and rat elongase genes. Because Fad2p is able to convert the endogenous oleic acid to linoleic acid, this allowed DGLA biosynthesis without the need to supply exogenous fatty acids on the media. Medium composition, cultivation temperature, and incubation time were examined to improve the yield of DGLA. Fatty acid content was increased by changing the medium from a standard synthetic dropout medium to a nitrogen-limited minimal medium (NSD). Production of DGLA was higher in the cells grown at 15�C than in those grown at 20�C, and no DGLA production was observed in the cells grown at 30�C. In NSD at 15�C, fatty acid content increased up until day 7 and decreased after day 10. When the cells were grown in NSD for 7 days at 15�C, the yield of DGLA reached 2.19 μg/mg of cells (dry weight) and the composition of DGLA to total fatty acids was 2.74%. To our knowledge, this is the first report describing the production of polyunsaturated fatty acids in S. cerevisiae without supplying the exogenous fatty acids.


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