Biology subjects

Jean, V.

Publications and source records attributed to Jean, V..

2 recordsLinked to original sources

bioRxiv2026

Development and pharmacological characterization of a stable HEK293 cell model for the study of human FLT3 signaling and its pharmacological modulation

Transient transfection in adherent cell lines has been used to study the function and pharmacology of the receptor tyrosine kinase FLT3, which is involved in myeloid leukemia and pain. However, transiently transfected cells express high levels of receptors, which show ligand-independent constitutive activity. We generated a stable recombinant cell line by transfecting a plasmid construct containing the full-length Flt3 cDNA into HEK293 cells. Four individual clones, numbered 6, 10, 15 and 17 were obtained. The FLT3 receptors expressed in the four clones showed high affinity for the ligand FL, as assessed in saturation and competition binding experiments, and FLT3 activation by FL effectively initiated the recruitment of the MAPK signaling pathway, a key mediator of downstream signaling cascades for the FLT3 receptor. Clone 6 showed highest receptor activation (nearly 6-fold increase upon FL stimulation), which was selected for further pharmacological characterization. FL-induced phospho-ERK levels were inhibited by quizartinib or BDT001 with potencies like those previously reported, and showed successful phosphorylation of the FLT3 receptor assessed by TYR969. The clone 6 of FLT3-transfected cell line therefore appears as a suitable and versatile cell line for assessing the potency of FLT3-based therapeutic candidates.

cell biology↗

bioRxiv2020

LARP6C regulates selective mRNA translation to promote pollen tube guidance in Arabidopsis thaliana.

In angiosperms, non-motile sperm cells are delivered to the ovules for fertilization via a guided growth of the pollen tube. RNA binding proteins are key regulators that control mRNA fate post-transcriptionally and thus essential for normal cell function. But very little is known on the mechanistic bases of mRNA regulations and trans-acting factors governing male-female signalling. Here we demonstrate that the evolutionarily conserved RNA binding protein LARP6C is necessary for pollen tube guidance and fertilization. larp6c loss-of-function mutants exhibit male induced fertility defects as mutant pollen tubes frequently are unable to find ovules for fertilization. In mature pollen, LARP6C localises with a pollen specific poly(A) binding protein to cytoplasmic foci likely containing mRNPs. With RNA immunoprecipitation and sequencing, we demonstrate that LARP6C is associated in vivo with mRNAs required for pollen tube guidance or polarized cell growth. We further demonstrate using in vitro and in planta transient assays that LARP6C binds 5-UTR box motifs to orchestrate the balance between translation, decay and storage of its mRNA targets. We propose a model where LARP6C maintains its mRNA target in translationally silent state likely to promote localized translation and guided pollen tube growth upon paracrine signalling.

plant biology↗