Characterization and functional analysis of lncRNA2690 in regulating the growth cycle of the hair follicle in rabbits.

Hair follicles (HFs) achieve hair growth and renewal by periodic regeneration. Therefore, exploring the key factors affecting hair growth in rabbits is of great significance for precisely breeding Angora rabbits and improving the competitiveness of the rabbit industry. Based on the results of our previous studies, lncRNA2690 was differentially expressed in the HF cycle using lncRNA-Seq, and the full-length sequence was annotated by bioinformatics analysis. The lncRNA2690 is 363 nt long and is found on chromosome 14 from 163 321 514 to 163 321 872. The lncRNA2690 was predicted to not have the coding ability through open reading frame and CPC2, and the nuclear-cytoplasmic separation experiment showed the lncRNA2690 to be highly expressed in the nucleus (p < 0.01). The expression pattern of lncRNA2690 was further analyzed in the different HF development stages of Angora rabbits using quantitative real-time PCR. The results showed that lncRNA2690 was periodically expressed in HF development, and the expression level was found to be high in the HF resting phases. The overexpression and knockdown of lncRNA2690 were found to significantly upregulate and downregulate the expression of the genes WNT2, CCND1, BMP2, LEF1, and SIAH1 in the rabbit dermal papilla cells (p < 0.01), promoting cell apoptosis and inhibiting cell proliferation (p < 0.01). This indicated that lncRNA2690 negatively regulates the periodic regeneration of the HFs in rabbits. These results provide a basis for the further study of lncRNA2690 in the HF growth cycle of Angora rabbits.

Engineering Rhodosporidium toruloides for limonene production.

BACKGROUND: Limonene is a widely used monoterpene in the production of food, pharmaceuticals, biofuels, etc. The objective of this work was to engineer Rhodosporidium toruloides as a cell factory for the production of limonene. RESULTS: By overexpressing the limonene synthase (LS), neryl pyrophosphate synthase (NPPS)/geranyl pyrophosphate synthase and the native hydroxy-methyl-glutaryl-CoA reductase (HMGR), we established a baseline for limonene production based on the mevalonate route in Rhodosporidium toruloides. To further enhance the limonene titer, the acetoacetyl-CoA thiolase/HMGR (EfMvaE) and mevalonate synthase (EfMvaS) from Enterococcus faecalis, the mevalonate kinase from Methanosarcina mazei (MmMK) and the chimeric enzyme NPPS-LS were introduced in the carotenogenesis-deficient strain. The resulting strains produced a maximum limonene titer of 393.5 mg/L. CONCLUSION: In this study, we successfully engineered the carotenogenesis yeast R. toruloides to produce limonene. This is the first report on engineering R. toruloides toward limonene production based on NPP and the fusion protein SltNPPS-CltLS. The results demonstrated that R. toruloides is viable for limonene production, which would provide insights into microbial production of valuable monoterpenes.

Microbial production of limonene and its derivatives: Achievements and perspectives.

Limonene and its derivatives have great market potential with diverse applications in food, pharmaceuticals, cosmetics, etc. Commercial production of limonene and its derivatives through extraction from plants suffers from the unstable market supply, while chemical synthesis of these compounds is hindered by high energy consumption and pollutant emission. Microbial biosynthesis provides a promising alternative approach for the sustainable supply of limonene and its derivatives. However, low efficiency and specificity of the biosynthetic enzymes and pathways in heterologous hosts make it still challenging for the commercialization of microbial limonene production. On the other hand, the limonene toxicity heavily reduces cellular fitness, which poses a serious challenge for improving limonene titer. Here, we critically review the recent progresses in engineering microbes for limonene biosynthesis and derivation with the emphasis on enzyme characterization and pathway optimization. In particular, we introduce the current trends in microbial limonene decoration for the biosynthesis of bio-active molecules such as α-terpineol and perillyl alcohol. We also discuss the feasible strategies for relieving limonene toxicity and enhancing the robustness of microbial cell factories.