measurement-poly-tail-length-from-drosophila-larva-brain-cell

Measurement of Poly A Tail Length from <em>Drosophila</em> Larva Brain and Cell Line

Polyadenylation is a crucial posttranscriptional modification that adds poly(A) tails to the 3' end of mRNA molecules. The length of the poly(A) tail is ...

University of Nevada, Reno

A frameshift mutation in  ()  was recently found from a rare human disorder with peripheral neurological conditions including hypotonia and areflexia. The YPEL gene family is highly conserved from yeast to human, but its members' functions are poorly defined. Moreover, the pathogenicity of the human  variant is completely unknown. We generated a  model of human  variant and a genetic null allele of  homolog of  (referred to as ). Gene-trap analysis suggests that  is predominantly expressed in subsets of neurons, including larval nociceptors. Analysis of chemical nociception induced by allyl-isothiocyanate (AITC), a natural chemical stimulant, revealed reduced nociceptive responses in both  frameshift and null mutants. Subsequent circuit analysis showed reduced activation of second-order neurons (SONs) in the pathway without affecting nociceptor activation upon AITC treatment. Although the gross axonal and dendritic development of nociceptors was unaffected, the synaptic contact between nociceptors and SONs was decreased by the  mutations. Furthermore, expressing dYPEL3 in larval nociceptors rescued the behavioral deficit in  frameshift mutants, suggesting a presynaptic origin of the deficit. Together, these findings suggest that the frameshift mutation results in  loss of function and may cause neurological conditions by weakening synaptic connections through presynaptic mechanisms.

Frameshift mutations of  alter the sensory circuit function in .

Dual leucine zipper kinase (DLK) plays a pivotal role in the development, degeneration, and regeneration of neurons. DLK can regulate gene expression post-transcriptionally, but the underlying mechanism remains poorly understood. The  DLK, Wallenda (Wnd), regulates the expression of Down syndrome cell adhesion molecule (Dscam) to control presynaptic arbor growth. This regulation is mediated by the 3' untranslated region (3'UTR) of  mRNA, which suggests that RNA binding proteins (RBPs) mediate DLK function. We performed a genome-wide cell-based RNAi screen of RBPs and identified the cytoplasmic poly(A)-binding protein, pAbp, as an RBP that mediates Wnd-induced increase in Dscam expression. Genetic analysis shows that Wnd requires  for promoting presynaptic arbor growth and for enhancing Dscam expression. Our analysis revealed that  mRNAs harbor short poly(A) tails. We identified a region in  3'UTR that specifically interacts with pAbp. Removing this region significantly reduced Wnd-induced increase in Dscam expression. These suggest that a noncanonical interaction of PABP with the 3'UTR of target transcripts is essential for DLK functions. The kinase DLK plays key roles in a multitude of neuronal responses, including axon development, neurodegeneration, and nerve injury. Previous studies show that DLK acts via mRNAs to regulate protein synthesis, but how DLK does so is poorly understood. This study demonstrates that DLK regulates the synthesis of Dscam through the poly(A)-binding protein PABP-C. Whereas PABP-C is known as a general translational activator, our study shows that DLK-mediated Dscam expression involves a noncanonical interaction between PABP-C and the  mRNA, which leads to a selective regulation of  translation by PABP-C. Thus, our study provides novel insights into the mechanisms that underlie the function of DLK and regulation of gene expression of PABP-C.

Article	Year
Frameshift mutations of alter the sensory circuit function in . Disease models & mechanisms\| PubMed ID: 32461240	2020
Dual Leucine Zipper Kinase Regulates Dscam Expression through a Noncanonical Function of the Cytoplasmic Poly(A)-Binding Protein. The Journal of neuroscience : the official journal of the Society for Neuroscience\| PubMed ID: 35764381	2022

Jung Hwan Kim

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