Entries by Arif Ashraf

CLASP sustains cell proliferation through a brassinosteroid signaling negative feedback loop ($) (Curr. Biol.)

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Brassinostreroid (BR) regulates the development of the root apical meristem. High levels of BR have inhibitory effects on cell production rates in the meristem and low levels show the opposite effect. Ruan, Halat et al. showed that BR regulates microtubule-associated CLASP (CLIP-Associated Protein) expression through the transcription factors BZR1 and BES1 in a BRI1-dependent manner, […]

Review: Harnessing synthetic chemistry to probe and hijack auxin signaling (New Phytol)

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Auxin has been studied since Charles Darwin observed the phototropic response. More recently, chemical genetic approaches using auxin agonists and antagonists have been applied to studies of auxin. Torii et al. review how synthetic chemistry and chemical genetics have provided insights into and new tools for controlling auxin signaling. The authors briefly discuss synthetic auxins […]

Epidermal expression of a sterol biosynthesis gene regulates root growth by a non-cell-autonomous mechanism in Arabidopsis (Development)

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The HYDRA1 (HYD1) gene is primarily expressed in the root epidermis and encodes a sterol Δ8-Δ7 isomerase. The hyd1 mutant has defects in growth and radial patterning of root development. Short et al. showed that although HYD1 is not expressed in the vascular cells, PIN1 localization and vascular patterning are abnormal in the hyd1 mutant. […]

The mechanism of SO2-induced stomatal closure differs from O3 and CO2 responses and is mediated by non-apoptotic cell death in guard cells ($) (Plant Cell Environ)

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Stomata opening and closing are regulated by guard cells. Airborne pollutants such as ozone, sulfur dioxide, and nitrogen dioxide cause stomatal closure. In this study, Lia Ooi et al. tried to understand the molecular mechanism of SO2-induced stomatal closure. SO2 is found in three forms in aqueous solution (H2CO3, HSO3–, SO32-) and the authors showed […]

Construction of a functional Casparian strip in non-endodermal lineages is orchestrated by two parallel signaling systems ($) (Curr. Biol.)

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The Casparian strip in the endodermis acts a barrier to allow the selective absorption of water and nutrients. Because of its cell-specific presence, the Casparian strip is considered a marker for functional endodermis. The cellular identity of endodermis is controlled by two transcription factors, SHR (SHORTROOT) and SCR (SCARECROW). In absence of SHR, the endodermal […]

PORCUPINE regulates development in response to temperature through alternative splicing ($) Nature Plants

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In this study, the authors performed strand-specific RNA sequencing of wild-type seedlings at 16°C, 23°C, and 27°C. They have found one candidate gene, a small nuclear robinucleoprotein family protein which contains a Like-Sm (LSM) domain. They named it as PORCUPINE (PCP) due to its “spiky” phenotype. As a temperature-specific mutant, pcp-1 shows dramatic developmental defects […]

Rapid and dynamic alternative splicing impacts the Arabidopsis cold response transcriptome ($) (Plant Cell)

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Plants experience abiotic stresses, such as alteration of temperature, and their responses have been studied through transcriptomics and proteomics approaches. X et al have studied how low temperature stress affects the transcriptome through alternative splicing. The author showed that a few hours after cold stress, rapid alternative splicing occurs. Interestingly, some of the early alternatively-spliced […]

The inhibitor Endosidin 4 targets SEC7 domain-type ARF GTPase exchange factors and interferes with subcellular trafficking ($) (Plant Cell)

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Subcellular trafficking helps determine the development of the plant through for instance the regulation of polar localization of auxin transporter PIN-FORMED (PIN) proteins. PIN trafficking or recycling is maintained by GNOM, a BFA-sensitive ARF GEF (ADP-ribosylation factor guanine nucleotide exchange factor). Much of what we know about ARF-GEFs comes from studies using the fungal inhibitor […]

Nonselective chemical inhibition of Sec7 domain-containing ARF-GEFs in Arabidopsis ($) (Plant Cell)

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ARF GEFs (ADP-ribosylation factor guanine nucleotide exchange factors) play a major role in the intracellular trafficking and eventually regulate developmental cues. As plants contain multiple ARF GEF with very similar sequences, chemical genetics approaches are more appropriate to uncover their function compared to classic genetic strategies. The fungal toxin Brefeldin A (BFA) targets the SEC7 […]