Biology subjects

Pierce, J.

Publications and source records attributed to Pierce, J..

3 recordsLinked to original sources

bioRxiv2018

KRAB Zinc Finger Proteins coordinate across evolutionary time scales to battle retroelements

KRAB Zinc Finger Proteins (KZNFs) are the largest and fastest evolving family of human transcription factors1,2. The evolution of this protein family is closely linked to the tempo of retrotransposable element (RTE) invasions, with specific KZNF family members demonstrated to transcriptionally repress specific families of RTEs3,4. The competing selective pressures between RTEs and the KZNFs results in evolutionary arms races whereby KZNFs evolve to recognize RTEs, while RTEs evolve to escape KZNF recognition5. Evolutionary analyses of the primate-specific RTE family L1PA and two of its KZNF binders, ZNF93 and ZNF649, reveal specific nucleotide and amino changes consistent with an arms race scenario. Our results suggest a model whereby ZNF649 and ZNF93 worked together to target independent motifs within the L1PA RTE lineage. L1PA elements eventually escaped the concerted action of this KZNF \"team\" over [~]30 million years through two distinct mechanisms: a slow accumulation of point mutations in the ZNF649 binding site and a rapid, massive deletion of the entire ZNF93 binding site.

evolutionary biology↗

bioRxiv2018

Temporal and spatial factors that influence magnetotaxis in C. elegans

Many animals can orient using the earths magnetic field. In a recent study, we performed three distinct behavioral assays providing evidence that the nematode Caenorhabditis elegans orients to earth-strength magnetic fields (Vidal-Gadea et al., 2015). In addition to these behavioral assays, we found that magnetic orientation in C. elegans depends on the AFD sensory neurons and conducted subsequent physiological experiments showing that AFD neurons respond to earth-strength magnetic fields. A new behavioral study by Landler et al. (2017) suggested that C. elegans does not orient to magnetic fields and raises issues that cast doubt on our study. Here we reanalyze Lander et al.s data to show how they appear to have missed observing positive results, and we highlight differences in experimental methods and interpretations that may explain our different results and conclusions. Moreover, we present new data from our labs together with replication by an independent lab to show how temporal and spatial factors influence the unique spatiotemporal trajectory that worms make during magnetotaxis. Together, these findings provide guidance on how to achieve robust magnetotaxis and reinforce our original finding that C. elegans is a suitable model system to study magnetoreception.

neuroscience↗

bioRxiv2017

Systematic Characterization Of Human 21st Chromosome Orthologs In Caenorhabditis elegans

Individuals with Down syndrome have neurological and muscle impairments due to an additional copy of the human 21st chromosome (HSA21). Only a few of ~200 HSA21 genes encoding protein have been linked to specific Down syndrome phenotypes, while the remainder are understudied. To identify poorly characterized HSA21 genes required for nervous system function, we studied behavioral phenotypes caused by loss-of-function mutations in conserved HSA21 orthologs in the nematode Caenorhabditis elegans. We identified ten HSA21 orthologs that are required for neuromuscular behaviors: cle-1 (COL18A1), cysl-2 (CBS), dnsn-1 (DONSON), eva-1 (EVA1C), mtq-2 (N6ATM1), ncam-1 (NCAM2), pad-2 (POFUT2), pdxk-1 (PDXK), rnt-1 (RUNX1), and unc-26 (SYNJ1). We also found that three of these genes are required for normal release of the neurotransmitter acetylcholine. This includes a known synaptic gene unc-26 (SYNJ1), as well as uncharacterized genes pdxk-1 (PDXK) and mtq-2 (N6ATM1). As the first systematic functional analysis of HSA21 orthologs, this study may serve as a platform to understand genes that underlie phenotypes associated with Down syndrome.\n\nARTICLE SUMMARYDown syndrome causes neurological and muscle dysfunction due to an extra 21st chromosome. This chromosome has over 200 genes, most of which are understudied. To address this, we studied whether reducing function of these gene equivalents in the worm C. elegans caused neuronal or muscle defects. We identified ten genes conserved between human and worm that mediate function of behaviors. Among these, we show the uncharacterized genes mtq-2 and pdxk-1 are important for synaptic transmission and are exclusively expressed in nervous system. Our analysis may reveal functions of poorly studied genes that affect nervous system function in Down syndrome.

neuroscience↗