Biology subjects

Yamashino, T.

Publications and source records attributed to Yamashino, T..

3 recordsLinked to original sources

bioRxiv2022

mRNA decapping machinery targets LBD3/ASL9 transcripts to allow developmental changes in Arabidopsis

Multicellular organisms perceive and transduce multiple cues to optimize development. Key transcription factors drive developmental changes, but RNA processing also contributes to tissue development. Here, we report that multiple decapping deficient mutants share developmental defects in apical hook, primary and lateral root growth. More specifically, LATERAL ORGAN BOUNDARIES DOMAIN 3 (LBD3)/ASYMMETRIC LEAVES 2-LIKE 9 (ASL9) transcripts accumulate in decapping deficient plants and can be found in complexes with decapping components. Accumulation of ASL9 inhibits apical hook, primary root growth and lateral root formation. Interestingly, exogenous auxin application restores lateral roots formation in both ASL9 over-expressors and mRNA decay-deficient mutants. Likewise, mutations in the cytokinin transcription factors type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs) ARR10 and ARR12 restore the developmental defects caused by over-accumulation of capped ASL9 transcript upon ASL9 overexpression. Most importantly, loss-of-function of asl9 partially restores apical hook and lateral root formation in decapping deficient mutants. Thus, the mRNA decay machinery directly targets ASL9 transcripts for decay, possibly to interfere with cytokinin/auxin responses, during development.

developmental biology↗

bioRxiv2021

A hierarchical transcriptional network activates specific CDK inhibitors that regulate G2 to control cell size and number in Arabidopsis

How cell size and number are determined during organ development remains a fundamental question in cell biology. Here, we identified a GRAS family transcription factor, called SCARECROW-LIKE28 (SCL28), with a critical role in determining cell size in Arabidopsis. SCL28 is part of a transcriptional regulatory network downstream of the central MYB3Rs that regulate G2 to M phase cell cycle transition. We show that SCL28 forms a dimer with the AP2-type transcription factor, AtSMOS1, which defines the specificity for promoter binding and directly activates transcription of a specific set of SIAMESE-RELATED (SMR) family genes, encoding plant-specific inhibitors of cyclin-dependent kinases and thus inhibiting cell cycle progression at G2 and promoting the onset of endoreplication. Through this dose-dependent regulation of SMR transcription, SCL28 quantitatively sets the balance between cell size and number without dramatically changing final organ size. We propose that this hierarchical transcriptional network constitutes a cell cycle regulatory mechanism that allows to adjust cell size and number to attain robust organ growth.

plant biology↗

bioRxiv2019

mRNA decapping machinery targets transcripts of the LBD3/ASL9 transcription factor to authorize formation of apical hook and lateral roots in Arabidopsis

Multicellular organisms perceive and transduce multiple cues to optimize developmental reprogramming and cell state switching. Key transcription factors drive developmental changes, but transitions also require the attenuation of previous states. Here, we demonstrate that the mRNA levels of the LATERAL ORGAN BOUNDARIES DOMAIN 3 (LBD3) / ASYMMETRIC LEAVES 2-LIKE 9 (ASL9) transcription factor are directly regulated by mRNA decapping. Capped ASL9 transcripts accumulate in decapping deficient plants and ASL9 mRNAs are found together with decapping components. Accumulation of ASL9 inhibits apical hook and lateral roots formation and interestingly, exogenous auxin application restores lateral roots formation in both ASL9 overexpressor and mRNA decay-deficient mutants. Moreover, mutations in the cytokinin transcription factors type-B ARABIDOPSIS RESPONSE REGULATORS (B-ARRs) ARR10 and ARR12 restore the developmental defects in apical hooking and lateral root formation caused by over-accumulation of capped ASL9 transcript upon ASL9 overexpression. Thus, the mRNA decay machinery directly targets ASL9 transcripts for decay to balance cytokinin/auxin responses during developmental reprogramming.

plant biology↗