Table 3. Biological functions of the 60 essential genes.
| let-Name | Chr | Gene Name | Protein Function | Pathway | Evolutionary Conservation |
|---|---|---|---|---|---|
| let-727 | III | R02F2.7 | Unknown | Unknown | N |
| let-728 | III | C23G10.8 | Unknown | Unknown | N |
| let-752 | III | lin-13 | Zinc-regulated transcription factor | In C. elegans, LIN-13 is involved in the tumor suppressor Rb-mediated transcriptional control process that leads to repression of vulval fates. | N |
| let-798 | III | wrm-1 | C. elegans β-catenin-like protein | In C. elegans, wrm-1 functions in noncanonical Wnt signaling pathways that specify cell fates in the early embryo. | N |
| let-342 | V | pmt-2 | Enzyme: phosphoethanolamine N-methyltransferase | PMT-2 lacks known mammalian orthologs, but has orthologs in the parasitic nematodes: fish, plants, and bacteria. PMT-1 only catalyzes the conversion of phosphoethanolamine to phospho-monomethylethanolamine, which is the first step in the PEAMT-pathway. | N |
| let-428 | V | K03B4.1 | Unknown | Unknown | N |
| let-455 | V | Y45G5AM.9 | Unknown | Unknown | N |
| let-463 | V | C04E6.11 | Unknown | Unknown | N |
| let-757/let-821 | III | fbn-1 | Extracellular matrix protein fibrillin | Fibrillin is a glycoprotein, which is essential for the formation of elastic fibers found in connective tissues. | N, I, M |
| let-782 | III | tag-189 | Unknown | Unknown | N, I, M |
| let-827 | III | cee-1 | Unknown | Unknown | N, I, M |
| let-327 | V | T08B1.1 | Member of solute carriers family | Predicted to have transmembrane transporter activity. | N, I, M |
| let-344 | V | sos-1 | Son of sevenless homolog | Its ortholog in mouse is a catalytic component of a trimeric complex that participates in transduction of signals from Ras to Rac by promoting the Rac-specific guanine nucleotide exchange factor activity. SOS-1 is involved in multiple Ras-dependent signaling pathways, which also interacts with LET-23 and LET-60 during vulval development. | N, I, M |
| let-348 | V | rft-1 | Member of solute carriers family, riboflavin transporter | In C. elegans, rft-1 exhibits riboflavin transporter activity and is involved in embryo development and receptor-mediated endocytosis. | N, I, M |
| let-423 | V | mig-6 | Highly similar to the extracellular matrix proteins papilin and lacunin | In C. elegans, MIG-6 activity is required for the ventral to dorsal phase of distal tip cell migration. | N, I, M |
| let-440 | V | ncx-2 | Sodium/calcium exchangers | Mediates the electrogenic exchange of Ca2+ against Na+ ions across the cell membrane, thereby contributes to the regulation of cytoplasmic Ca2+ levels and Ca2+-dependent cellular processes. | N, I, M |
| let-702 | III | hmgr-1 | Enzyme: 3-hydroxy-3-methylglutaryl-coenzyme A reductase | HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, which is a rate-limiting step in sterol biosynthesis. | N, I, M, F |
| let-712 | III | prp-8 | mRNA splicing: pre-mRNA-processing-splicing factor | Its ortholog in yeast is a component of the U4/U6-U5 snRNP complex and participates in spliceosomal assembly through its interaction with the U1 snRNA. | N, I, M, F |
| let-732 | III | rpb-2 | Enzyme: RNA polymerase II (B) subunit | The second largest subunit B150 of RNA polymerase II is the enzyme that produces the primary transcript. | N, I, M, F |
| let-736 | III | cdk-12 | Enzyme: cyclin-dependent kinase | Its ortholog in yeast phosphorylates both the RNA pol II subunit to affect transcription, and the ribosomal protein to increase translational fidelity. | N, I, M, F |
| let-741 | III | rars-1 | Enzyme: arginyl(R) aminoacyl tRNA synthetase in mitochondria | The tRNA synthetase catalyzes the attachment of an amino acid to its cognate transfer RNA molecule. | N, I, M, F |
| let-743 | III | ZK686.2 | Enzyme: ATP-dependent RNA helicase | Its orthologs in yeast and human are involved in the biogenesis of ribosomal subunits. | N, I, M, F |
| let-747 | III | algn-1 | Enzyme: chitobiosyldiphosphodolichol β-mannosyltransferase | Mannosyltransferase is involved in asparagine-linked glycosylation in the endoplasmic reticulum. | N, I, M, F |
| let-753 | III | C34E10.10 | Ribosome-related protein: rRNA-processing protein | The protein is involved in ribosomal subunit biogenesis. | N, I, M, F |
| let-763 | III | T08A11.2 | mRNA splicing: splicing factor 3B subunit 1 | U2-snRNP associated splicing factor forms extensive associations with the branch site-3′ splice site-3′ exon region upon prespliceosome formation. | N, I, M, F |
| let-764 | III | byn-1 | Mammalian bystin (adhesion protein) related protein | Its ortholog in yeast is required for pre-rRNA processing and 40S ribosomal subunit synthesis. | N, I, M, F |
| let-771 | III | rfl-1 | Enzyme: ubiquitin activating enzyme | RFL-1 activity is required for proper cytokinesis and spindle orientation. | N, I, M, F |
| let-774 | III | rps-3 | Ribosome-related protein: ribosomal protein, small subunit | Protein component of the small ribosomal subunit involved in protein biosynthesis. | N, I, M, F |
| let-784 | III | gop-3 | Component of the Sorting and Assembly Machinery (SAM) complex | SAM complex binds precursors of beta-barrel proteins and facilitates their outer membrane insertion. | N, I, M, F |
| let-786 | III | unc-116 | Kinesin-related motor protein | Its ortholog in yeast is required for mitotic spindle assembly and chromosome segregation. | N, I, M, F |
| let-799 | III | ddx-23 | Enzyme: ATP-dependent RNA helicase | Its ortholog in yeast is involved in mRNA decay and rRNA processing. | N, I, M, F |
| let-826 | III | mrps-18C | Ribosome-related protein: ribosomal protein (small) in mitochondria | Ribosomal subunit biogenesis | N, I, M, F |
| let-829 | III | atp-2 | Enzyme: mitochondrial ATP synthase subunit | Evolutionarily conserved enzyme complex that is required for ATP synthesis. | N, I, M, F |
| let-832 | III | F09F7.4 | Enzyme: 3-hydroxyisobutyryl-CoA hydrolase | Biological process unknown | N, I, M, F |
| let-972 | III | hsp-110 | Heat shock protein | Its ortholog in yeast is a ATPase component of the heat shock protein Hsp90 chaperone complex and serves as nucleotide exchange factor to load ATP onto the SSA class of cytosolic Hsp70s. | N, I, M, F |
| let-326 | V | rab-1 | Enzyme: Rab family GTPase | Intracellular vesicle trafficking, such as the ER-to-Golgi step of the secretory pathway. | N, I, M, F |
| let-331 | V | prx-6 | Peroxisomal biogenesis factor | Its ortholog in yeast heterodimerizes with Pex1p and participates in the recycling of the peroxisomal signal receptor from the peroxisomal membrane to the cystosol. | N, I, M, F |
| let-332 | V | C05C8.7 | Enzyme: Mannose phosphate isomerase | Its ortholog in yeast catalyzes the interconversion of fructose-6-P and mannose-6-P, which is required for early steps in protein mannosylation. | N, I, M, F |
| let-334 | V | slc-17.8 | Member of solute carriers family | Predicted to have transmembrane transporter activity. | N, I, M, F |
| let-335 | V | C37C3.2 | Translation initiation factor | Based on the homology to yeast, the products of C37C3.2 are predicted to function during translation initiation as GTPase activators to stimulate GTP hydrolysis by eIF2-GTP-Met-tRNAi. | N, I, M, F |
| let-338 | V | rpac-40 | Enzyme: RNA polymerase I/III (A/C) shared subunit | Common component of RNA polymerases I and III, which synthesize ribosomal RNA precursors and small RNAs, such as 5S rRNA and tRNAs. | N, I, M, F |
| let-343 | V | cpsf-2 | Cleavage and polyadenylation specificity factor | Required for 3′ processing, splicing, and transcriptional termination of mRNAs and snoRNAs. | N, I, M, F |
| let-346 | V | soap-1 | HEAT repeat-containing protein | SOAP is involved in a pathway that controls the apical delivery of E-cad and morphogenesis. | N, I, M, F |
| let-350 | V | C37H5.5 | Nucleolar complex protein-like DNA replication regulator | Its ortholog in yeast binds to chromatin at active replication origins and is required for pre-RC formation as well as maintenance during DNA replication licensing. | N, I, M, F |
| let-402 | V | erfa-1 | Translation termination factor | Subunit of the heterodimeric translation release factor complex involved in the release of nascent polypeptides from ribosomes. | N, I, M, F |
| let-408 | V | snap-1 | α-soluble NSF attachment protein | Its ortholog in mouse is required for vesicular transport between the endoplasmic reticulum and the Golgi apparatus. | N, I, M, F |
| let-409 | V | asns-1 | Enzyme: asparagine synthase (glutamine-hydrolyzing) | Catalyzes the synthesis of L-asparagine from L-aspartate in the asparagine biosynthetic pathway. | N, I, M, F |
| let-410 | V | dlst-1 | Enzyme: dihydrolipoamide S-succinyltransferase | Its ortholog in yeast is a component of the mitochondrial alpha-ketoglutarate dehydrogenase complex, which catalyzes the oxidative decarboxylation of alpha-ketoglutarate to succinyl-CoA in the TCA cycle. | N, I, M, F |
| let-411 | V | xpo-1 | Exportin-1, an importin-β-like protein orthologous to Drosophila, vertebrates, and yeast exportin-1/CRM1 | XPO-1 is predicted to function as a nuclear export receptor for proteins containing leucine-rich nuclear export signals. | N, I, M, F |
| let-415 | V | hsp-6 | Nuclear-encoded mitochondrion-specific chaperone that is a member of the DnaK/Hsp70 superfamily of molecular chaperones | In C. elegans, hsp-6 is involved in the mitochondrial unfolded protein response. | N, I, M, F |
| let-417 | V | ceh-34 | Homeobox protein | In C. elegans, ceh-34 activity is required for regulation of the programmed cell death of a pharyngeal neuron, the sister of the M4 motor neuron. | N, I, M, F |
| let-419 | V | pqn-51 | Transcription initiation factor IIA | Its ortholog in yeast is involved in transcriptional activation and acts as antirepressor or coactivator. | N, I, M, F |
| let-420 | V | adss-1 | Enzyme: adenylosuccinate synthetase | Catalyzes the first step in the synthesis of adenosine monophosphate from inosine 5′monophosphate during purine nucleotide biosynthesis. | N, I, M, F |
| let-422 | V | hmgs-1 | Enzyme: hydroxymethylglutaryl-CoA synthase | Its ortholog in yeast catalyzes the formation of HMG-CoA from acetyl-CoA and acetoacetyl-CoA. | N, I, M, F |
| let-424 | V | vars-1 | Enzyme: valyl-aminoacyl tRNA synthetase in mitochondria | The tRNA synthetase catalyzes the attachment of an amino acid to its cognate transfer RNA molecule. | N, I, M, F |
| let-439 | V | M03F8.3 | mRNA splicing: crooked neck pre-mRNA splicing factor | The crooked neck gene of Drosophila is essential for embryogenesis and is thought to be involved in cell cycle progression and pre-mRNA splicing. | N, I, M, F |
| let-442 | V | C05C8.2 | Ribosome-related protein: small subunit processome component | A nucleolar protein required for rRNA synthesis and ribosomal assembly. | N, I, M, F |
| let-447 | V | egl-8 | Enzyme: phospholipase C β | In yeast, the ortholog (Plc1p) and inositol polyphosphates are required for acetyl-CoA homeostasis, which regulates global histone acetylation. | N, I, M, F |
| let-459 | V | hpo-18 | Enzyme: ATP synthase | Unknown | N, I, M, F |
| let-470 | V | F11A3.2 | Translation initiation factor | These proteins help stabilize the formation of the functional ribosome around the start codon and also provide regulatory mechanisms in translation initiation. | N, I, M, F |
The table is sorted by evolutionary conservation, chromosome (Chr), and lethal name (let-Name). N, nematodes; I, invertebrates (Drosophila); M, mammals (mouse, human); F, fungi (Saccharomycetaceae).