A Genetic Screen for Mutants with Supersized Lipid Droplets in Caenorhabditis elegans

To identify genes that regulate the dynamics of lipid droplet (LD) size, we have used the genetically tractable model organism Caenorhabditis elegans , whose wild-type LD population displays a steady state of size with an upper limit of 3 μm in diameter. From a saturated forward genetic screen of 6.7 × 105 mutagenized haploid genomes, we isolated 118 mutants with supersized intestinal LDs often reaching 10 μm. These mutants define nine novel complementation groups, in addition to four known genes ( [maoc-1][1] , [dhs-28][2] , [daf-22][3] , and [prx-10][4] ). The nine groups are named drop (lipid droplet abnormal) and categorized into four classes. Class I mutants [drop-5][5] and [drop-9][6] , similar to [prx-10][4] , are up-regulated in [ACS-22][7]-[DGAT-2][8]-dependent LD growth, resistant to LD hydrolysis, and defective in peroxisome import. Class II mutants [drop-2][9] , [drop-3][10] , [drop-6][11] , and [drop-7][12] are up-regulated in LD growth, are resistant to LD hydrolysis, but are not defective in peroxisome import. Class III mutants [drop-1][13] and [drop-8][14] are neither up-regulated in LD growth nor resistant to LD hydrolysis, but seemingly up-regulated in LD fusion. Class IV mutant [drop-4][15] is cloned as [sams-1][15] and, different to the other three classes, is [ACS-22][7]-independent and hydrolysis-resistant. These four classes of supersized LD mutants should be valuable for mechanistic studies of LD cellular processes including growth, hydrolysis, and fusion. [1]: http://www.wormbase.org/db/get?name=WBGene00017123;class=Gene [2]: http://www.wormbase.org/db/get?name=WBGene00000991;class=Gene [3]: http://www.wormbase.org/db/get?name=WBGene00013284;class=Gene [4]: http://www.wormbase.org/db/get?name=WBGene00006946;class=Gene [5]: http://www.wormbase.org/db/get?name=WBGene00270298;class=Gene [6]: http://www.wormbase.org/db/get?name=WBGene00270302;class=Gene [7]: http://www.wormbase.org/db/get?name=WBGene00017012;class=Gene [8]: http://www.wormbase.org/db/get?name=WBGene00010296;class=Gene [9]: http://www.wormbase.org/db/get?name=WBGene00270296;class=Gene [10]: http://www.wormbase.org/db/get?name=WBGene00270297;class=Gene [11]: http://www.wormbase.org/db/get?name=WBGene00270299;class=Gene [12]: http://www.wormbase.org/db/get?name=WBGene00270300;class=Gene [13]: http://www.wormbase.org/db/get?name=WBGene00270295;class=Gene [14]: http://www.wormbase.org/db/get?name=WBGene00270301;class=Gene [15]: http://www.wormbase.org/db/get?name=WBGene00008205;class=Gene