Lightnews — Scholar-powered news

Parichy Lab | Dave Parichy

@dparichy.bsky.social

420 followers 620 following 27 posts

Posts Media Videos Starter Packs

Parichy Lab | Dave Parichy @dparichy.bsky.social · Aug 26

Nemo needs gap junctions, too. New preprint with Marleen Klann, Vincent Laudet, et al. showing anemonefish Snowflake mutant due to E42K substitution in Connexin Gja5b. Found exact same E42K in zebrafish gja5b (= leopard) by ENU, to the nucleotide! Details, inferences: www.biorxiv.org/content/10.1...

gap junction mutant phenotypes in clownfish and zebrafish

1 17 49

Parichy Lab | Dave Parichy @dparichy.bsky.social · Apr 30

Huge congrats to Ray Keller on his election to the National Academy of Sciences! Ray isn’t on Bluesky but that shouldn’t stop anyone from letting him know how well deserved this is, or the impact he’s had generally. Certainly his work was a major reason I ended up in dev bio.

1 3 19

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

Like other dominant pigment pattern mutants, this allele is named for a surrealist, in this case the Spanish-Mexican painter Remedios Varo. Here is one of her works, Allegory of Winter (1948), which as a bonus seems to show dendrites extending from the "cells."

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

These and other genetic analyses in zebrafish, as well as studies of mutants in other species, suggest a model for evolution of Mitf requirements in pigment cell lineages.

1 1

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

This phenotype is recapitulated when the Mitf null allele is combined with a null allele for Tfec.

2 1

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

In both species the allele is semi-dominant due to mutation in DNA binding domain. Although recessive alleles of Mitf in zebrafish have melanophore defects, we found that this allele also has defects in xanthophores, too.

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

With forward genetic screen, found exact same mutation in fish as identified many years ago in mouse.

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 24

New paper out from grad student Katia Korzeniwsky and collaborators with roles for Mitfa transcription factor in pigment cell development and genetic interactions with related transcription factor Tfec.
dx.doi.org/10.1111/pcmr...

1 4 11

Parichy Lab | Dave Parichy @dparichy.bsky.social · Mar 5

Cool paper out from former lab member Braedan McCluskey’s dissertation, with John Postlethwait. Shows role of hybridization in zebrafish genome evolution. Interesting implications for pigment pattern evolution.

academic.oup.com/g3journal/ar...

The hybrid history of zebrafish

Abstract. Since the description of zebrafish (Danio rerio) in 1822, the identity of its closest living relative has been unclear. To address this problem,

academic.oup.com

4 5

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 22

For sure… did my best to make that clear!

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 22

“Yeah what about it” was pretty much exactly what McGuire(R) VA-5 staffer had to say when contacted

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 22

VA-5 (R) staffer: nothing to be done, government just can’t afford these costs anymore.

1 2

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

As usual, a heroic job from our own folks, especially Dylan, and great fun working with our collaborators, and of course thanks to NIH and the MIRA mechanism for letting us go where the science leads.

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

We believe this is all pretty cool because (i) it shows how a differentiated cell type has been “repurposed” to have an entirely new phenotype and (ii) it shows the importance of positional information even in a species best known for self-organizing its pattern.

1 3

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

Putting it all together, we think this is what’s going on.

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

So how do BMP (and Agouti) drive fate conversion? Transcription factors Foxd3 (well known) and Runx3 (not well known in pigment biology) are downstream of BMP and necessary and sufficient to effect melanin loss and purine gain.

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

But even knocking out both Agouti genes didn’t eliminate all the white cells so we looked further and identified an additional role for BMPs, which pattern the fin more generally. Here BMPs signal through non-canonical receptors including Rgmb.

1 1

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

We hypothesized that positional information specifies where transdifferentiation should happen. scRNA-seq, mutants and transgenes showed that one such cue is Agouti-related Asip1, which acts in concert with another Agouti peptide, Asip2b,

1 2

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

Here’s a kickass FIB-SEM movie of a transitional cell, showing organelles in various states of degradation or development (this took a week of instrument time).

1 1

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

We showed previously that white cells—melanoleucophores—differentiate from melanophores. Here we show how this occurs, with massive changes in transcriptome, turnover of pigmentary organelles, loss of melanin and gain of white guanine crystals.

1 1

Parichy Lab | Dave Parichy @dparichy.bsky.social · Feb 18

New NIH funded research from our group now out. We are interested in development and evolution of cell types and adult phenotypes. In this paper, postdoc Dylan Huang and collaborators asked how a pigmentary ornament of bright white cells develops on the fin of zebrafish. www.pnas.org/doi/10.1073/...

1 10 22

Parichy Lab | Dave Parichy @dparichy.bsky.social · Jan 26

Ontogenetic, nuptial, physiological? Several possible contacts.

Reposted by Parichy Lab | Dave Parichy

Kai The Fish Guy @kaithefishguy.bsky.social · Dec 20

Cirrhilabrus hygroxerus, the Monsoon Fairy Wrasse

Two in two days! I’m feeling generous. Ok I’m gonna speed run this one.

Hygro = wet
Xeros = dry
Wet + dry = monsoon = weather profile of Darwin = type location of this species

A small species of fairy wrasse (a type of fish) with bright red pendulous pelvic fins. The body is bicolored - black above, silver below. The head is chestnut orange and the tail is scintillating blue.

9 82

Reposted by Parichy Lab | Dave Parichy

Simon J. Brandl @gobyone.bsky.social · Dec 18

🚨New postdoc positions available: we are looking for 2 postdoctoral researchers to join a large, collaborative effort to document, describe, and investigate the biodiversity of tiny, cryptobenthic fishes in the Indo-Pacific 🤏🐠🧪. More details: fishandfunctions.com/join%F0%9F%9...

Please repost 🦑🧪

1 71 100

Parichy Lab | Dave Parichy @dparichy.bsky.social · Dec 6

Congrats! Look forward to reading this.