BackgroundCircadian rhythm, regulated by both internal and external environment of the body, is a multi-scale biological oscillator of great complexity. On the molecular level, thousands of genes exhibit rhythmic transcription, which is both organ- and species-specific, but it remains a mystery whether some common factors could potentially explain their rhythmicity in different organs. In this study we address this question by analyzing the transcriptome data in 12 mouse organs to determine such major impacting factors.ResultsWe found a strong positive correlation between the transcriptional level and rhythmic amplitude of circadian rhythmic genes in mouse organs. Further, transcriptional level could explain over 70% of the variation in amplitude. In addition, the functionality and tissue specificity were not strong predictors of amplitude, and the expression level of rhythmic genes was linked to the energy consumption associated with transcription.ConclusionExpression level is a single major factor impacts the behavior of rhythmic genes in mouse organs. This single determinant implicates the importance of rhythmic expression itself on the design of the transcriptional system. So, rhythmic regulation of highly expressed genes can effectively reduce the energetic cost of transcription, facilitating the long-term adaptive evolution of the entire genetic system.

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Intraflagellar transport (IFT) represents a bidirectional dynamic process that carries cargo essential for cilia building and the maintenance of ciliary function, which is important for the locomotion of single cells, intracellular and intercellular signalling transduction. Accumulated evidence has revealed that defects in IFT cause several clinical disorders. Here, we determined the role of IFT80, an IFT‐B protein that is mutated in Jeune asphyxiating thoracic dystrophy. Using the RNAi method in the ciliate Paramecium as model, we found that loss of IFT80 prevents cilia biogenesis and causes strong cell lethality. A specific antibody against IFT80 was also prepared in our study, which labelled IFT80 in cilia of Paramecium. GFP fusion experiments were performed to illustrate the dynamic movement of IFT‐A and IFT‐B proteins in cilia of Paramecium; then, we found that the depletion of IFT80 in cells prevents IFT‐A and IFT‐B proteins from entering the cilia. Our results showed the distribution change of other IFT proteins in cells that were depleted of IFT80, and we discuss the possible roles of IFT80 in Paramecium.

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Background Lonicera Japonica Thunb. is a perennial, semi-evergreen and twining vine in the family of Caprifoliaceae, which is widely cultivated in Asia. Thus far, L. japonica is often used to treat some human diseases including COVID-19, H1N1 influenza and hand-foot-and-mouth diseases, however, the regulatory mechanism of intrinsic physiological processes during different floral developmental stages of L. japonica remain largely unknown. Results The complete transcriptome of L. japonica was de novo-assembled and annotated, generating a total of 195850 unigenes, of which 84657 could be functionally annotated. 70 candidate genes involved in flowering transition were identified and the flowering regulatory network of five pathways was constructed in L. japonica. The mRNA transcripts of AGL24 and SOC1 exhibited a downward trend during flowering transition and followed by a gradual increase during the flower development. The transcripts of AP1 was only detected during the floral development, whereas the transcript level of FLC was high during the vegetative stages. The expression profiles of AGL24, SOC1, AP1 and FLC genes indicate that these key integrators might play the essential and evolutionarily conserved roles in control of flowering switch across the plant kingdom. We also identified 54 L. japonica genes encoding enzymes involved in terpenoid biosynthesis pathway. Most highly expressed genes centered on the MEP pathway, suggesting that this plastid pathway might represent the major pathway for terpenoid biosynthesis in L. japonica. In addition, 33 and 31 key genes encoding enzymes involved in the carotenogenesis and anthocyanin biosynthesis pathway were identified, respectively. PSY transcripts gradually increased during the flower development, supporting its role as the first rate-limiting enzyme in carotenoid skeleton production. The expression level of most anthocyanin biosynthetic genes was dramatically decreased during the flower developmental stages, consistent with the decline in the contents of anthocyanin. Conclusion These results identified a large number of potential key regulators controlling flowering time, flower color and floral scent formation in L. japonica, which improves our understanding of the molecular mechanisms underlying the flower traits and flower metabolism, as well as sets the groundwork for quality improvement and molecular breeding of L. japonica.