This is a truly terrible idea.

Los Angeles agrees! We need to #StandUpForScience2025!

Celebrating four of my most brilliant colleagues in the inaugural @uclastemcell.bsky.social BSCRC Women in Stem Cell Science symposium.

LA scientists and supporters! Please share - our local Stand Up For Science event is at noon, 3/7 at the Wilshire Federal Building. @latimes.com @laist.com

Yesica Mercado-Ayon in the Butler lab won the People's Choice award in the @uclastemcell.bsky.social microscopy contest! Here's her image for #fluorescentfriday #fluorescencefriday: "A tree made of neurons".

Viral tracing (yellow) in the mouse adult spinal cord (cyan, nuclei; magenta, axons). Image by the very talented Soizic Riche. #fluorescencefriday #fluorescentfriday

Sign on the on ramp of I-76 right by U Penn … that’s quite some trolling of U Penn Medicine by NYU Langone 😳

Our first #fluorescenceFriday (or is it #fluorescentFriday ?) image - a transverse section through a sciatic nerve, labeled to reveal the axons (NF, green) and Schwann cells (S100, red). Image from Soizic Riche.

One of my favorite movies from my lab (generated by Soizic Riche) - mCherry+ E14 rat DRG axons branching and fasciculating as they grow on matrigel.

Thus, the presence of netrin1 may stabilize the production of Bmp inhibitors, such as the inhibitory Smad, Smad7. Such inhibitors then suppress Bmp signaling and permitting the specification of the intermediate dI4–dI6 fates. In short, a really enjoyable Butler lab collaboration! 9/9

Sandeep Gupta took a bioinformatic approach using our dI stem cell model to assess the mechanism by which netrin1 regulates cell fate. He identified that netrin1 does not appear to act directly as a Bmp inhibitor but rather regulates mRNA processing. 8/9

Together, these results argued that netrin1 acts from the intermediate spinal cord to regionally confine Bmp signaling to the dorsal spinal cord. 7/9

Work from many labs, including the Butler lab, has shown that Bmps act from the dorsal midline to specify the dorsal-most interneurons, dI1, dI2 and dI3. Moreover, there is a boundary of netrin1 expression immediately adjacent to the dorsal-most spinal cord. 5/9

However, Sandy rapidly hit a brick wall, because in the presence of high levels of netrin1 after in ovo electroporation, the commissural (dI1) axons disappeared. This is not a small phenotype; the axons completely disappear. 3/9

This paper grew out of an unexpected observation, by Sandy Alvarez, as part of her thesis work in the Butler lab. She was expressing tagged netrin1 in the chicken spinal cord, with the goal of live imaging the passage of netrin from progenitors -> pial surface -> axons. 2/9

E10.5 mouse spinal cord (neural tube), labeled with Sox2 (red, neural progenitors), nestin (green, radial fibers) and neurofilament (blue, axons). The ventral motor columns are the most developed structure at this early time point.

First Bluesky post from the Butler lab: meet Matilda, our lab dog!

Matilda alternates between sleeping under my desk and over enthusiastically greeting lab members, here newly promoted Assistant Professor, Sandeep Gupta.