GO:0042759 long-chain fatty acid biosynthetic process: Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0042759 describes the biological process that produces long-chain fatty acids with aliphatic tails of 13 to 22 carbons.
• Long-chain fatty acids are essential for energy storage, membrane structure, and signaling, and their biosynthesis is tightly regulated.
• Key enzymes include FASN, ELOVL family members, and desaturases such as SCD and FADS2, which elongate and desaturate fatty acids.
• Dysregulation of long-chain fatty acid biosynthesis contributes to metabolic disorders, cardiovascular disease, and cancer.
• CRISPR-based models (knockout, point mutation, knock-in, overexpression) enable causal dissection of genes in this pathway.
• Understanding this process informs nutrition, especially infant development and brain accretion of long-chain polyunsaturated fatty acids.
Description
Long-chain fatty acids (LCFAs) are carboxylic acids with aliphatic tails of 13 to 22 carbons, and their biosynthesis is a fundamental metabolic process in all kingdoms of life. The Gene Ontology term GO:0042759, long-chain fatty acid biosynthetic process, encompasses the chemical reactions and pathways that result in the formation of these molecules. LCFAs serve as major energy substrates, building blocks of membrane phospholipids, and precursors to signaling lipids, making their synthesis central to cellular homeostasis. In humans, the pathway is particularly important in liver, adipose tissue, heart, and brain, where it supports energy metabolism and structural integrity. Research into GO:0042759 has accelerated due to its links to metabolic diseases, cardiovascular disorders, and cancer. The pathway involves a series of enzymatic steps, including de novo synthesis by fatty acid synthase (FASN), elongation by ELOVL enzymes, and desaturation by stearoyl-CoA desaturase (SCD) and fatty acid desaturases (FADS1/2). Each step is regulated transcriptionally and allosterically, often through nuclear receptors such as PPARs and SREBP-1c. For researchers, GO:0042759 provides a framework to study how cells allocate carbon flux toward storage, membrane synthesis, or signaling. Disruptions in this process are implicated in lipotoxicity, insulin resistance, and tumor progression. This article synthesizes authoritative QuickGO data and verified PubMed literature to outline the definition, mechanisms, key genes, disease relevance, and experimental models for studying long-chain fatty acid biosynthesis.
long-chain fatty acid biosynthetic process At A Glance
| GO ID | GO:0042759 |
|---|---|
| GO term | long-chain fatty acid biosynthetic process |
| Ontology | biological_process |
| Synonym | long-chain fatty acid anabolism; long-chain fatty acid biosynthesis; long-chain fatty acid formation; long-chain fatty acid synthesis |
| Major function | Production of fatty acids with 13-22 carbon aliphatic tails for energy storage, membrane synthesis, and signaling |
| Key enzymes | FASN, ELOVL1-7, SCD, FADS1, FADS2, ACACA, ACACB |
| Substrates | Acetyl-CoA, malonyl-CoA, NADPH |
| Cellular location | Cytosol (de novo synthesis), endoplasmic reticulum (elongation/desaturation) |
| Related pathways | Fatty acid elongation, fatty acid desaturation, lipid storage, PPAR signaling |
What Is GO:0042759?
GO:0042759, long-chain fatty acid biosynthetic process, is defined as the chemical reactions and pathways resulting in the formation of a long-chain fatty acid, which is a fatty acid with an aliphatic tail containing 13 to 22 carbons. This process includes the de novo synthesis of fatty acids from acetyl-CoA and malonyl-CoA, as well as elongation and desaturation steps that produce long-chain saturated, monounsaturated, and polyunsaturated fatty acids.
Why Is long-chain fatty acid biosynthetic process Important in Cell Biology?
Long-chain fatty acid biosynthesis is essential for maintaining energy balance, membrane fluidity, and lipid signaling. Its dysregulation is a hallmark of metabolic syndrome, cardiovascular disease, and cancer, making it a prime target for therapeutic intervention and biomarker discovery.
• Provides energy storage as triglycerides, protecting against lipotoxicity.
• Supplies structural components of cell membranes, influencing fluidity and function.
• Generates precursors for signaling molecules such as eicosanoids and endocannabinoids.
• Supports brain development and function, particularly long-chain polyunsaturated fatty acids.
• Contributes to milk fat production in lactation.
• Dysregulation leads to insulin resistance, hepatic steatosis, and cardiovascular disease.
• Overexpression of lipogenic enzymes is common in many cancers.
• Informs dietary recommendations for essential fatty acids.
• Enables metabolic engineering of oil-producing organisms.
• Serves as a target for drugs against obesity and diabetes.
What Happens During long-chain fatty acid biosynthetic process?
De novo synthesis of saturated fatty acids
In simple terms: The cell builds a basic 16-carbon saturated fat from small molecules.
De novo fatty acid synthesis occurs in the cytosol and begins with the carboxylation of acetyl-CoA to malonyl-CoA by acetyl-CoA carboxylase (ACACA/ACACB). Fatty acid synthase (FASN) then uses acetyl-CoA and malonyl-CoA in a repeating cycle of condensation, reduction, dehydration, and reduction to produce palmitate (16:0). This process consumes NADPH and is regulated by SREBP-1c and PPARs.
Elongation to very-long-chain fatty acids
In simple terms: Enzymes add more carbons to the basic fat to make longer chains.
Palmitate can be further elongated by membrane-bound elongases (ELOVL1-7) in the endoplasmic reticulum. Each elongation cycle adds two carbons using malonyl-CoA and NADPH. ELOVL enzymes exhibit substrate specificity: ELOVL6 elongates C16 to C18, while ELOVL1, 3, and 7 act on longer and polyunsaturated fatty acids.
Desaturation by stearoyl-CoA desaturase (SCD)
In simple terms: An enzyme introduces a double bond into the fat chain.
SCD (also known as delta-9 desaturase) converts saturated fatty acids (e.g., stearate, C18:0) to monounsaturated fatty acids (e.g., oleate, C18:1) by introducing a double bond at the delta-9 position. This reaction requires oxygen and NADH or NADPH. SCD is a key regulator of membrane fluidity and is highly expressed in lipogenic tissues.
Polyunsaturated fatty acid (PUFA) synthesis
In simple terms: The cell makes omega-3 and omega-6 fats by adding double bonds and elongating chains.
Long-chain PUFAs such as arachidonic acid (20:4 n-6), EPA (20:5 n-3), and DHA (22:6 n-3) are synthesized from essential fatty acids (linoleic and alpha-linolenic acid) through alternating desaturation and elongation steps. FADS2 and FADS1 introduce double bonds, while ELOVL2 and ELOVL5 elongate the chain. This pathway is critical for brain and retinal function.
Regulation of flux and substrate availability
In simple terms: The cell decides how much fat to make based on energy needs and signals.
The pathway is regulated at multiple levels: transcriptional control by SREBP-1c, ChREBP, and PPARs; allosteric regulation of ACC by citrate and palmitoyl-CoA; and post-translational modification of FASN and SCD. Insulin promotes lipogenesis, while AMPK inhibits it. Long-chain fatty acids themselves can feedback to inhibit ACC and FASN.
Key Genes Involved in GO:0042759 long-chain fatty acid biosynthetic process
The following genes encode enzymes and regulators that directly participate in or control long-chain fatty acid biosynthesis.
| Gene | Major Role | Research Relevance |
|---|---|---|
| FASN | Catalyzes de novo synthesis of palmitate from acetyl-CoA and malonyl-CoA | Target in cancer and metabolic disease; knockout reduces lipogenesis |
| ACACA | Converts acetyl-CoA to malonyl-CoA, rate-limiting step | Regulated by AMPK; knockout is embryonic lethal |
| ACACB | Inhibits fatty acid oxidation, promotes synthesis | Knockout improves insulin sensitivity in mice |
| ELOVL1 | Elongates very-long-chain fatty acids | Skin barrier function; knockout causes neonatal lethality |
| ELOVL2 | Elongates PUFAs, especially DHA | Role in retinal and brain function; knockout impairs vision |
| ELOVL3 | Elongates saturated and monounsaturated fatty acids | Involved in skin and sebaceous gland lipids |
| ELOVL5 | Elongates PUFAs | Knockout alters hepatic lipid composition |
| ELOVL6 | Elongates C16 to C18 saturated and monounsaturated fatty acids | Knockout protects against diet-induced insulin resistance |
| SCD | Desaturates saturated fatty acids to monounsaturated | Knockout improves leptin sensitivity and reduces adiposity |
| FADS1 | Desaturates PUFAs (delta-5 desaturase) | Associated with inflammatory and metabolic traits |
| FADS2 | Desaturates PUFAs (delta-6 desaturase) | Essential for PUFA synthesis; polymorphisms affect fatty acid levels |
| SREBF1 | Transcription factor controlling lipogenic gene expression | Overexpression promotes lipogenesis; knockout reduces fat mass |
| PPARG | Nuclear receptor regulating adipogenesis and lipid storage | Target of thiazolidinediones; knockout causes lipodystrophy |
| MLXIPL | ChREBP, glucose-responsive transcription factor | Knockout impairs carbohydrate-induced lipogenesis |
| NR1H3 | LXR-alpha, regulates cholesterol and fatty acid synthesis | Knockout reduces lipogenesis |
| INSIG1 | Retains SREBP in ER, inhibiting lipogenesis | Knockout increases lipogenesis |
| SCAP | Escorts SREBP to Golgi for activation | Knockout blocks SREBP processing |
| DGAT1 | Catalyzes final step of triglyceride synthesis | Knockout protects against diet-induced obesity |
How Is long-chain fatty acid biosynthetic process Regulated?
Long-chain fatty acid biosynthesis is regulated by a network of transcription factors and signaling pathways. SREBP-1c is the master transcriptional regulator of lipogenic genes, including FASN, ACACA, and SCD, and is activated by insulin and liver X receptors (LXRs). ChREBP (MLXIPL) mediates glucose-induced lipogenesis. PPARs, particularly PPAR-alpha and PPAR-gamma, modulate fatty acid oxidation and storage. AMPK phosphorylates and inhibits ACC, reducing malonyl-CoA availability. Additionally, feedback inhibition by long-chain fatty acids and their acyl-CoA derivatives fine-tunes enzyme activity.
long-chain fatty acid biosynthetic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SCD | Obesity, insulin resistance, cancer | Knockout and overexpression in hepatocytes and adipocytes |
| ELOVL6 | Insulin resistance, hepatic steatosis | Liver-specific knockout and knock-in mice |
| FASN | Cancer, metabolic syndrome | CRISPR knockout in cancer cell lines; point mutation to disable catalytic activity |
| FADS2 | Neurodevelopmental disorders, inflammation | Knock-in of human polymorphisms in cell models |
| DGAT1 | Lipotoxicity, obesity | Knockout mice and overexpression in adipose tissue |
Metabolic syndrome and cardiovascular disease
Dysregulated long-chain fatty acid biosynthesis contributes to insulin resistance, hepatic steatosis, and dyslipidemia. Elevated SCD activity is associated with obesity and cardiovascular risk, while ELOVL6 deficiency improves insulin sensitivity in mice. Myocardial fatty acid metabolism is critical for heart function, and imbalances can lead to cardiomyopathy.
Cancer
Many cancers exhibit upregulated de novo lipogenesis, with overexpression of FASN, SCD, and ELOVL enzymes supporting rapid proliferation and membrane synthesis. Inhibition of these enzymes reduces tumor growth in preclinical models, making the pathway a therapeutic target.
Neurodevelopmental and neurodegenerative disorders
Long-chain PUFAs, especially DHA, are essential for brain development and function. Defects in PUFA synthesis, due to FADS or ELOVL mutations, are linked to cognitive deficits and retinal dysfunction. Impaired fatty acid metabolism is also observed in Alzheimer's disease and other neurodegenerative conditions.
Lipotoxicity and organ dysfunction
Excessive accumulation of long-chain fatty acids can cause lipotoxicity in non-adipose tissues, contributing to beta-cell dysfunction, cardiomyopathy, and kidney injury. Triglyceride synthesis via DGAT1 protects against lipotoxicity by storing fatty acids as inert lipids.
From long-chain fatty acid biosynthetic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ELOVL6 improve insulin sensitivity? | Liver-specific knockout mouse or CRISPR knockout in HepG2 cells |
| Does a specific SCD polymorphism alter desaturase activity? | Point mutation knock-in in HEK293 or HepG2 cells |
| Can FASN overexpression drive lipogenesis in cancer cells? | Overexpression of FASN in low-lipogenic cancer cell lines |
| What is the role of FADS2 in PUFA synthesis? | Knockout and knock-in of FADS2 in neuroblastoma cells |
| Does tagging endogenous ELOVL5 affect its localization? | Tagged knock-in of ELOVL5 with fluorescent protein in HeLa cells |
| Can CRISPR library screening identify synthetic lethal partners of FASN? | Genome-wide CRISPR knockout library in cancer cell lines |
How to Study the long-chain fatty acid biosynthetic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lipidomics (LC-MS/MS) | Abundance of individual fatty acid species | Quantify changes in chain length and saturation |
| RNA-seq | Expression levels of lipogenic genes | Assess transcriptional regulation |
| CRISPR knockout screening | Genes required for fatty acid synthesis or viability | Identify synthetic lethal targets |
| 13C metabolic flux analysis | Flux through de novo synthesis and elongation | Measure pathway activity |
| Western blot | Protein levels of FASN, SCD, ELOVLs | Validate knockout or overexpression |
| Immunofluorescence | Subcellular localization of enzymes | Study ER vs. cytosolic localization |
| Co-immunoprecipitation | Protein-protein interactions in the pathway | Identify regulatory complexes |
Lipidomics and mass spectrometry
Mass spectrometry-based lipidomics quantifies the abundance of individual long-chain fatty acid species, revealing changes in chain length and saturation upon genetic perturbation. This method is essential for validating CRISPR models.
RNA-seq and transcriptomics
RNA sequencing measures expression of genes in the biosynthetic pathway, such as FASN, ELOVLs, and SCD, providing insights into transcriptional regulation and compensatory responses.
CRISPR screening and functional genomics
Genome-wide CRISPR knockout or activation screens can identify genes that are essential for long-chain fatty acid biosynthesis or that confer sensitivity to inhibitors. These screens link genotype to lipid phenotype.
Metabolic flux analysis
Stable isotope tracing with 13C-labeled substrates (e.g., glucose, acetate) followed by mass spectrometry measures flux through the biosynthetic pathway, distinguishing de novo synthesis from elongation and desaturation.
How CRISPR Can Be Used to Study GO:0042759 long-chain fatty acid biosynthetic process
Knockout
CRISPR knockout of genes such as FASN, SCD, or ELOVL6 in cell lines or animal models ablates enzyme function, allowing researchers to study loss-of-function phenotypes in lipid metabolism, cell proliferation, and disease progression.
Point Mutation
Introducing specific point mutations (e.g., in the catalytic domain of FASN or SCD) via CRISPR base editing or homology-directed repair enables separation of enzymatic activity from non-catalytic functions, and models human polymorphisms.
Knock-in
Knock-in of reporter tags (e.g., GFP, HA) or disease-associated variants (e.g., FADS2 polymorphisms) at endogenous loci allows real-time tracking of protein localization and function under physiological expression levels.
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of genes like FASN or SCD drives lipogenesis, modeling cancer and metabolic disease states, and enabling gain-of-function studies.
How EDITGENE Supports long-chain fatty acid biosynthetic process Research
Researchers studying long-chain fatty acid biosynthetic process-related genes often need to determine whether a candidate gene is causally involved in lipid synthesis, how specific mutations affect enzyme activity, and whether targeting the pathway can reverse disease phenotypes. EDITGENE provides end-to-end CRISPR solutions to answer these questions with rigor and reproducibility.
Contact EDITGENE today to design your custom CRISPR model for long-chain fatty acid biosynthetic process research.
Frequently Asked Questions About long-chain fatty acid biosynthetic process
What is GO:0042759?
GO:0042759 is the Gene Ontology term for long-chain fatty acid biosynthetic process, the set of reactions that produce fatty acids with 13 to 22 carbon tails.
What genes are involved in long-chain fatty acid biosynthetic process?
Key genes include FASN, ACACA, ELOVL1-7, SCD, FADS1, FADS2, and transcription factors like SREBF1 and PPARG.
What is the difference between long-chain and short-chain fatty acids?
Long-chain fatty acids have 13-22 carbons, while short-chain have fewer than 6 and medium-chain 6-12; they differ in metabolism and transport.
How is long-chain fatty acid biosynthesis regulated?
It is regulated by SREBP-1c, ChREBP, PPARs, and AMPK, which respond to insulin, glucose, and energy status.
What diseases are associated with defects in long-chain fatty acid biosynthesis?
Metabolic syndrome, cardiovascular disease, cancer, and neurodevelopmental disorders.
Can CRISPR be used to study long-chain fatty acid biosynthesis?
Yes, CRISPR knockout, knock-in, and overexpression models enable causal studies of genes in this pathway.
What methods measure long-chain fatty acid biosynthesis?
Lipidomics, RNA-seq, metabolic flux analysis, and CRISPR screens are commonly used.
Why are long-chain polyunsaturated fatty acids important?
They are critical for brain development, vision, and inflammation resolution.
What is the role of ELOVL enzymes?
ELOVL enzymes elongate fatty acyl chains in the endoplasmic reticulum, determining chain length and saturation.
How does SCD contribute to fatty acid biosynthesis?
SCD introduces a double bond at delta-9, converting saturated to monounsaturated fatty acids.
Conclusion
GO:0042759, long-chain fatty acid biosynthetic process, is a central metabolic pathway with profound implications for health and disease. Its enzymes and regulators are promising targets for therapeutic intervention in cancer, diabetes, and cardiovascular disorders. CRISPR-based models provide powerful tools to dissect the causal roles of individual genes and to discover new regulatory mechanisms. Continued research into this pathway will advance our understanding of lipid biology and open new avenues for treatment.
References
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