Entries by Linda Palmer

Twin-Positive Motifs Function as Specific Plastid Targeting Signals

Precise trafficking of proteins to their proper destinations in the cell, whether to an organelle, a membrane, or the cytoplasm, is required for optimal cellular function. Because most plastid proteins are nucleus-encoded and translated in the cytoplasm, proper targeting and import relies on the presence of specific N-terminal transit peptide sequences. But what signals direct […]

Exosome-Deficient Mutants Reveal Rare Promoter Upstream Transcripts (PROMPTs) in Arabidopsis

In eukaryotes and archaea, protein-coding DNA is transcribed to messenger RNA (mRNA) via a preinitiation complex (PIC) composed of over 100 proteins, among them regulatory proteins, numerous transcription factors, and RNA polymerase II—the enzyme that produces precursor messenger RNA (pre-mRNA). Although transcription is traditionally represented by the synthesis of a single unidirectional transcript along the […]

RNA polymerase II transcription: cleave to elongate

Antosz et al. show that the ability of RNA polymerase II to cleave transcripts is required for proper transcription and plant growth. Wojciech Antosz and Klaus Grasser, University of Regensburg https://doi.org/10.1105/tpc.19.00891   Background: In plants as in other eukaryotes, nuclear RNA polymerase II (RNAPII) transcribes protein-coding genes to produce mRNAs, which are then translated to […]

Phosphorus sensing in Chlamydomonas by TORC1 subunit LST8

Couso et al. developed a TOR kinase assay for Chlamydomonas and show how subunit LST8 senses phosphorus availability and modulates cell growth. Plant Cell https://doi.org/10.1105/tpc.19.00179 By I. Couso, M.E. Pérez-Pérez, M.M. Ford, E. Martínez-Force, L.M. Hicks, J.G. Umen, and J.L. Crespo. Background: Because nutrient stress seriously affects healthy growth in photosynthetic organisms, understanding how nutrients […]

The Arabidopsis GPT1 transporter is Essential in Both Plastids and Peroxisomes

Baune et al. explore the roles of a metabolite transporter in two different locations in a single cell. Plant Cell https://doi.org/10.1105/tpc.19.00959  By Marie-Christin Baune, Hannes Lansing, Antje von Schaewen University of Münster, Germany   Background: The oxidative pentose-phosphate pathway (OPPP) is found in all multicellular organisms. In plants, this pathway is essential due to reactions […]

The Way Out: A Transcriptionally Unique Group of Endosperm Cells Implicated in Nutrient Export to the Embryo

Successful development of the maize (Zea mays) kernel requires proper nutrient transport and signaling among its genetically distinct components: the embryo that gives rise to the next generation, the endosperm that nourishes the embryo, and the maternal tissues that surround the embryo and the endosperm (reviewed in Widiez et al., 2017). During its early development, […]

Regulation of Carotenoid Pigmentation in Flowers

Stanley et al. Identify a protein in the model plant monkeyflower (Mimulus) required for chromoplast development and carotenoid biosynthesis. Plant Cell https://doi.org/10.1105/tpc.19.00755  By Lauren Stanley and Yao-Wu Yuan, University of Connecticut  Background: Carotenoids are yellow, orange, or red pigments that give many flowers and fruits their brilliant colors. In order to make and accumulate carotenoids […]

The R-loop: An Additional Chromatin Feature for Gene Regulation in Arabidopsis

R-loops are three-stranded nucleic acid structures composed of a DNA-RNA hybrid and a displaced single-stranded DNA. R-loops are stable structures as they form an intermediate A/B conformation of the RNA-DNA hybrid that is more stable than the B form of dsDNA or A form of the dsRNA. Recent evidence reveals the occurrence of R-loops in […]

SHORTROOT coordinates phloem development via two pathways

Kim et al. examine how plants coordinate sieve element and companion cell development. Plant Cell https://doi.org/10.1105/tpc.19.00455 By Hyoujin Kim1 and Ji-Young Lee1,2, School of Biological Sciences, College of Natural Science, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea1 Plant Genomics and Breeding Institute, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea2  Background: Phloem […]