Chromosomal localization of the human gene for palmitoyl-CoA ligase (FACL1)

Expression and vitamin D3 regulation of long-chain fatty-acid-CoA ligase 3 in human prostate cancer cells

We found previously that long-chain fatty-acid-CoA ligase 3 (FACL3), a critical enzyme for activation of long-chain fatty acids, was upregulated by 1α, 25(OH)(2)D(3) at an mRNA and enzyme activity levels in prostate cancer cells. Our further study indicated that the FACL3 mediated 1α,25(OH)(2)D(3) inhibition of fatty acid synthase (FAS), which is associated with many cancers, including prostate cancer. In the current study, we investigated an FACL3 protein expression and its regulation by 1α, 25(OH)(2)D(3) and its synthetic analogs EB1089 and CB1093 in prostate cancer cells. The results showed that the expression of an FACL3 protein was upregulated by 1α, 25(OH)(2)D(3), EB1089 and CB1093 in LNCaP cells, consistent with their upregulation of an FACL3 mRNA expression. In addition, the FACL3 expression was found to be markedly low at both mRNA and protein levels in more transformed prostate cancer PC-3 and DU145 cells compared with less transformed LNCaP cells. The data suggest that decreased FACL3 expression might be associated with a more malignant phenotype of prostate cancer.

Relevance between lipid metabolism-associated genes and rat liver regeneration

AIM

Lipids are important in constituting cell structure and participating in many biological processes, particularly in energy supplementation to cells. The aim of the present study is to elucidate the action of lipid metabolism-associated genes on rat liver regeneration (LR).

METHODS

Lipid metabolism-associated genes were obtained by collecting website data and retrieving related articles, and their expression changes in the regenerating rat liver were checked by the Rat Genome 230 2.0 array.

RESULTS

In total, 280 genes involved in lipid metabolism were proven to be LR-associated by comparing the gene expression discrepancy between the partial-hepatectomy and sham-operation groups. The initial and total expression numbers of these genes occurring in the initial phase, G(0)/G(1) transition, cell proliferation, cell differentiation, and structure-functional rebuilding of LR were 128, 33, 135, 6, and 267, 147, 1026, 306, respectively, illustrating that these genes were initially expressed mainly in the initiation stage and functioned in different phases. Upregulation (850 times) and downregulation (749 times), as well as 25 types of expression patterns, showed that the physiological and biochemical activities were diverse and complicated in LR.

CONCLUSION

According to the results of the chip detection, it was presumed that fatty acid synthesis at 24-66 h, leukotriene and androgen synthesis at 16-168 h, prostaglandin synthesis at 2-96 h, triglyceride synthesis at 18-24 h, glycosphingolipid synthesis at 0.5-66 h, metabolism of phosphatidyl inositol and sphingomyelin at 2-16 h, and cholesterol catabolism at 30-168 h were enhanced. Throughout almost the whole LR, the genes participating in estrogen, glucocorticoid, and progesterone synthesis, and triglyceride catabolism were upregulated, while phospholipid and glycosphingolipid catabolism were downregulated.

Molecular characterization of a rabbit long-chain fatty acyl CoA synthetase that is highly expressed in the vascular endothelium

The formation of coenzyme A thioesters from long-chain fatty acids represents a metabolic branch point. We have isolated, cloned and sequenced a long-chain fatty acyl CoA synthetase (LCFACoAS) that is localized to the endothelium of rabbit heart and aorta. Immunofluoresence and in situ hybridization studies show intense staining of the intimal layer of the aorta and coronary vessels. The microvessels, including the capillaries, of the coronary circulation also show intense immunofluoresence. The enzyme shares only about 30% to 70% homology with the primary amino acid sequence of the other known LCFACoAS. There is a region of 44 amino acids at the carboxy terminus, which is unique to the vascular enzyme. This domain contains the most hydrophobic region of the molecule, indicating that it may function as a membrane anchoring site. These results suggest that this LCFACoAS represents a novel isoform, whose functional significance remains to be determined.

RNA interference of peroxisome-related genes in C. elegans: a new model for human peroxisomal disorders

RNA-mediated interference (RNAi) for the posttranscriptional silencing of genes was used to evaluate the importance of various peroxisomal enzymes and peroxins for the development of Caenorhabditis elegans and to compare the roles of these proteins in the nematode to their roles in yeasts and humans. The nematode counterparts of the human ATP-binding cassette half-transporters, the enzymes alkyldihydroxyacetonephosphate synthase and Delta(3,5)-Delta (2,4)-dienoyl-CoA isomerase, the receptors for peroxisomal membrane and matrix proteins (Pex19p and Pex5p), and components of the docking and translocation machineries for matrix proteins (Pex13p and Pex12p) are essential for the development of C. elegans. Unexpectedly, RNAi silencing of the acyl-CoA synthetase-mediated activation of fatty acids, the alpha- and beta-oxidation of fatty acids, the intraperoxisomal decomposition of hydrogen peroxide, and the peroxins Pex1p, Pex2p, and Pex6p had no apparent effect on C. elegans development. The described analysis of functional gene knockouts through RNAi provides a basis for the use of C. elegans as a valuable model system with which to study the molecular and physiological defects underlying the human peroxisomal disorders.

FACL4, a new gene encoding long-chain acyl-CoA synthetase 4, is deleted in a family with Alport syndrome, elliptocytosis, and mental retardation

We observed a family in which two boys were diagnosed with Alport syndrome, elliptocytosis, and mental retardation and carried a large deletion of the Xq22.3-q23 region, encompassing the COL4A5 gene. This suggests the possibility of a new contiguous gene syndrome. In an attempt to characterize the genes contributing to this complex phenotype, we have isolated a gene encoding a new long-chain acyl-CoA synthetase (FACL4 or LACS4) from the region deleted in these patients. Among several ESTs identified by searching the human gene map database maintained at the National Center for Biotechnology Information, using the map position as a query, only one was deleted in the patients. RACE products containing the entire ORF were subsequently generated. Northern blot analysis showed a 5-kb mRNA expressed in several tissues except for liver and lung. Brain shows a longer transcript, possibly reflecting the use of a brain-specific upstream ATG start codon. FACL4 encodes a predicted protein product of 670 amino acids (711 in brain), with a remarkable level of conservation compared to the rat acyl-CoA synthetases ACS4 and brain-specific ACS3 protein sequences. We are investigating the possibility that the absence of this enzyme may play a role in the development of mental retardation or other signs associated with Alport syndrome in the family.