(1) Wu HW, Fajiculay E, Wu JF, Yan CCS, Hsu CP* and Wu SH* (2022) Noise reduction by upstream open reading frames. Nature Plants 8(5):474-480
(2) Huang CK, Lin WD and Wu SH* (2022) An improved repertoire of splicing variants and their potential roles in Arabidopsis photomorphogenic development. Genome Biol. 23:50
(3) Jang GJ, Yang JY, Hsieh HL and Wu SH* (2019) Processing bodies control the selective translation for optimal development of Arabidopsis young seedlings. Proc Natl. Acad. Sci. USA 116:6451-6456
(4) Chen GH, Liu MJ, Xiang Y, Sheen J and Wu SH* (2018) Target of rapamycin (TOR) and ribosomal protein S6 (RPS6) transmit light signals to enhance protein translation in de-etiolating Arabidopsis seedlings. Proc Natl. Acad. Sci. USA 115:12823-12828
(5) Wu JF, Tsai HL, Joanito I, Wu YC, Chang CW, Li YH, Wang Y, Hong J. C, Chu JW, Hsu CP, and Wu SH* (2016) LWD-TCP complex activates the morning gene CCA1 in Arabidopsis. Nature Commun. 7: 13181
(6) Wu SH* (2014) Gene expression regulation in photomorphogenesis from the perspective of central dogma. Ann. Rev. Plant Biol. 65:311-333
(7) Liu MJ, Wu SH, Wu JF, Lin WD, Wu YC, Tsai TY, Tsai HL, Wu SH* (2013) Translational landscape of photomorphogenic Arabidopsis. Plant Cell 10: 3699-710
(8) Wang Y, Wu JF, Nakamichi N, Sakakibara H, Nam HG, Wu SH* (2011) LIGHT-REGULATED WD1 and PSEUDO-RESPONSE REGULATOR9 form a positive feedback regulatory loop in the Arabidopsis circadian clock. Plant Cell 23: 486–498
(9) Chen HM, Chen LT, Patel K, Li YH, Baulcombe D. and Wu SH* (2010) 22-nucleotide RNA triggers secondary siRNA biogenesis in plants. Proc. Natl. Acad. Sci. USA 107, 15269-74
(10) Chen HM, Li YH and Wu SH* (2007) Bioinformatic prediction and experimental validation of a microRNA-directed tandem trans-acting siRNA cascade in Arabidopsis. Proc. Natl. Acad. Sci. USA 104, 3318-3323
|
| The operation of the circadian clock allows organisms to synchronize their internal biological activities with the external 24-hour rhythmic light/dark or temperature cues for optimal growth and developmental fitness. Maintaining a robust circadian clock in plants relies on precise coordination of transcriptional activation/repression, post-transcriptional, and posttranslational modifications of clock mRNAs and proteins. Bursts of transcription and translation can lead to fluctuations in both mRNA and protein levels. The oscillating nature of circadian genes makes them particularly vulnerable to stochastic gene expression. Mechanisms to reduce variability, or ‘noise’, of gene expression would help to stabilize the production of clock mRNAs and proteins. Upstream open reading frames (uORFs) in the 5’ leader sequences of 30–50% of mRNAs in diverse eukaryotic organisms can repress protein production of the coding sequences. mRNA of the evening gene TIMING OF CAB EXPRESSION 1 (TOC1) has four AUG-initiated uORFs in its 5′ leader sequence. We assessed the action mechanism of uORFs-mediated translational repression of the TOC1 protein production and put this regulation into the biological context of clock operation. Results showed that although the cells can synthesize a wide range of TOC1 mRNAs, uORFs buffer a stable TOC1 protein level by reducing the protein production rate. Such precision of TOC1 protein levels is required for a robust operation of the circadian clock in Arabidopsis. |