Danielle Spitzer

It doesn’t even count to 25 correctly (16, 17, __, 18, 18)

When echinoid (ed) mutant clones (white) and wild-type twin clones (red) are generated in the developing Drosophila eye (right), the mutant tissue is eliminated. However, if wild-type twin clones are removed so that most eye tissue is mutant (left), the ed mutant cells survive and the eyes overgrow. See Research Article by Spitzer et al.

Issue 15 is complete!

On the cover: When echinoid (ed) mutant clones (white) and wild-type twin clones (red) are generated in the developing Drosophila eye (right), the mutant tissue is eliminated. See Research Article by Spitzer et al.

journals.biologists.com/dev/article/...

Don’t lose your Ed: adhesion molecules in growth and survival

This Research Highlight showcases the work from Danielle Spitzer, William Sun, Anthony Rodríguez-Vargas, and Iswar Hariharan:

journals.biologists.com/dev/article/...

Thank you!!!! 🪰💙

To find out more about their work, we spoke to first author Danielle Spitzer @dspitzer.bsky.social and corresponding author Iswar Hariharan, Professor at the University of California, Berkeley, USA:

journals.biologists.com/dev/article/...

The people behind the papers – Danielle Spitzer and Iswar Hariharan Neighbouring cells have a huge influence on one another in the developing epithelia, but the role of cell–cell adhesion molecules in context-dependent neighbour interactions remains unclear. In a new ...

For some more behind-the-scenes on this paper, check out this interview with me and Iswar! (8/8) journals.biologists.com/dev/article/...

Picture of William Sun. Below are data that William collected: Effect of reducing ed function in the posterior compartment on Ilp8 expression. hh-Gal4, Ilp8-GFP (L) discs do not express detectable levels of Ilp8-GFP, but when hh-Gal4 drives expression of ed-RNAi (M), Ilp8-GFP is elevated in a pattern that coincides with the expected location of the unmarked posterior compartment.

Picture of Anthony Rodríguez-Vargas. Below are data that Anthony collected: Phenotypes of imaginal discs containing clones generated with a FLP-out Gal4 and UAS-otk2-RNAi transgene. Clones are marked by GFP or RFP, as indicated. A cyst-like clone in K is shown at higher magnification in L and an orthogonal view is provided in L′. 

A HUGE thanks to my co-authors: Anthony Rodríguez-Vargas helped with the genetic screen, and William Sun conducted many key experiments after I graduated (including the one showing that ed- discs secrete Ilp8, all of S5 and S7, and much of S6). Science is a team sport! (7/8)

Model summary of phenotypes caused by Echinoid loss and proposed mechanisms. (A,A′) Clones of echinoid mutant cells are eliminated from mosaic tissues. Ed-depleted cells have decreased Diap1 expression, which predisposes them to death by apoptosis, and increased apical Ft. In the wild-type neighbors bordering the ed clones, levels of Yki targets, including Diap1, bantam and four-jointed, are elevated. This may confer a competitive advantage to the wild-type neighbors, which could facilitate the elimination of ed clones from mosaic tissue (A′). (B,B′) When ed mutant tissue is abundant (e.g. in an entire organ), mutant cells persist and the resulting organs overgrow. This overgrowth is facilitated by Ilp8 secretion, which delays pupariation. Slow-growing ed mutant tissue fails to arrest at the proper final size, leading to overgrown organs (B′).

We propose a revised model of how Ed functions in growth regulation, emphasizing that context matters. Also, Ed is known to affect EGFR, Notch, Hippo, cell adhesion, and membrane trafficking...so mutant phenotypes may involve complex effects on multiple pathways/processes at once (6/8)

(E-K) Time course of growth of imaginal discs expressing either w-RNAi (E,F) or ed-RNAi (G-K) in the GFP-marked posterior compartment. All larvae expressing w-RNAi pupariated soon after 120 h. Much older larvae were observed in the population expressing ed-RNAi; examples of discs from these larvae are shown.

Although ed- clones are eliminated, ed- compartments/organs overgrow. There are still high levels of apoptosis in these tissues, but the organs keep growing for an extended period of time (this involves secretion of Ilp8 which delays pupariation) and the organs can eventually become very large (5/8)

Hippo pathway reporters are altered in and around echinoid clones. (A,A′) RFP-marked (A) ed-RNAi clone shows decreased expression of a diap1 transcriptional reporter generated using eight copies of the Hippo-response element (HRE) from the diap1 locus (A′). (B,B′) GFP-marked (B) ed-RNAi clones stained with anti-Diap1 (B′). (C,C′) RFP-labeled (C) ed-RNAi clone shows decreased fj-lacZ expression (C′). Wild-type cells adjacent to the clone show increased fj-lacZ expression. (D,D′) GFP-labeled (D) ed-RNAi clone shows decreased ban-lacZ expression (D′). Wild-type cells adjacent to the clone show increased ban-lacZ expression. 

It has been proposed that Ed functions in the Hippo pathway to restrict expression of pro-growth Yki target genes. However, we found that Ed loss led to reduced expression of some Yki target genes in ed- clones! We sometimes observed a border effect with increased expression in WT neighbors (4/8)

Wing discs containing GFP-marked clones expressing either UAS-w-RNAi (A,C,E) or UAS-ed-RNAi (B,D,F). Heat shocks of 12 min (A,B), 15 min (C,D) and 30 min (E,F) generate clones at progressively higher density.

Imaginal discs containing GFP-marked clones expressing UAS-w-RNAi (E) or UAS-ed-RNAi (high clone density) (F). Anti-Dcp-1 staining of the same discs are shown in E′,F′. Images were taken at a basal z-plane where Dcp-1 staining was most prominent. Arrowheads in F,F′ highlight examples of anti-Dcp1 staining near clone boundaries.

Discs expressing UAS-ed-RNAi alone (low clone density) in GFP-marked clones, stained with anti-Diap1 (G′,H′). Arrowheads in G,G′ show the location of clones where reduced Diap1 is apparent.

When ed- clones are generated in the presence of WT cells, mutant clones are eliminated. This is because ed- cells have elevated apoptosis rates and reduced levels of Diap1. This is especially pronounced at clone borders, suggesting that competition with WT cells may be involved (3/8)

Summary figure of genetic screen. 153 initial candidates included 136 Ig-Superfamily and 17 cadherin genes. 53 were excluded, 26 not screened, 65 were not a hit, and 9 were hits. ama, beat-Vc, Cont, shg, and side-VII had a growth disadvantage. Ft and Ds had a round shape. Ed and otk2 had a growth disadvantage and round shape.

We conducted a screen to identify adhesion molecules that regulate the growth of mutant clones. We focused on Ed since reducing its function in mosaics led to clone undergrowth/elimination, but previous work suggests that these mutant cells should overgrow. Hmmmmmm…… (2/8)

My PhD work from @hariharanlab.bsky.social is finally out in @dev-journal.bsky.social! We investigated an interesting paradox: how can reduced function of the adhesion molecule Echinoid (Ed) cause seemingly opposite phenotypes—overgrowth and elimination—in different contexts? (1/8)

Fig.3. echinoid clones are generated and then die, especially when more wild-type tissue is present. (A-F) Wing discs containing GFP-marked clones expressing either UAS-w-RNAi (A,C,E) or UAS-ed-RNAi (B,D,F). Heat shocks of 12 min (A,B), 15 min (C,D) and 30 min (E,F) generate clones at progressively higher density. Scale bar in H applies to H-K. Scale bar in A applies to A-F.

The cell-adhesion molecule Echinoid promotes tissue survival and separately restricts tissue overgrowth.

Read this #OA Research Article by Danielle Spitzer
@dspitzer.bsky.social , William Sun, Anthony Rodríguez-Vargas, and Iswar Hariharan:

journals.biologists.com/dev/article/...

Important to note that this work (and nearly all US based biomedical research) would not have been possible without funding from the #NIH.

Ontogeny of the vagal gut-brain axis Gut-brain communication is a key component of homeostasis which regulates behaviors such as appetite and reward. Intestinal entero-endocrine cells (EECs) translate nutrient intake into signals which a...

First Bluesky post! I'm excited to share a preprint from my postdoctoral work where we 1) define the developmental mechanisms guiding formation of a vagal gut-brain circuit and 2) discover that this circuit regulates much more than just appetite. www.biorxiv.org/content/10.1...

Four black and white views of a developing bat embryo on a black background.

It's Monday again, but try not to have a "bat" attitude 🦇 Instead, check out these views of a bat embryo showing developing cartilage and vasculature!

The image was captured by previous #MBL Embryology student @dspitzer.bsky.social with a ZEISS Axio Zoom.V16 microscope and an Axiocam 702 camera.

I Just Quit My Job at the NIH. Slashing DEI Is Going to Haunt the Future of Medicine. We’d only started to correct a major gap in understanding.

I quit my job at the NIH last month, in large part because it seemed like I could no longer honestly write about topics like health equity. so I wrote about it for Slate instead 🧪 slate.com/technology/2...

Want to join the UNC Biology teaching faculty team? We’re hiring a new TAP! Please share. unc.peopleadmin.com/postings/297...

The University of Pittsburgh pauses its Ph.D. admissions process amid research funding uncertainty A spokesperson for the University told WESA Friday that the school has "temporarily paused additional Ph.D. offers of admission," while Pitt works to understand how proposed federal funding cuts could...

The University of Pittsburgh confirmed Friday that there would be no new Ph.D. offers of admission while Pitt works to understand how reduced federal aid could impact the institution.

Slide 12: Reality: NIH consistently spends about 27% of grant money on indirect costs. Graph showing costs for tope 30 universities are all approx. at 27% Slide 13: Major, abrupt funding cuts were announced and blocked within the last week. The policy announced last Friday would cap reimbursement to universities for indirect costs at 15%. At least as of yesterday, this has been temporarily halted. Screenshots of news articles: "New NIH policy: Pitt faces big cut in federal research money[Pittsburgh Post-Gazette" "‘Science is non-partisan’: Pitt researchers face NIH funding freeze [THEPITTNEWS]" "Judge freezes NIH funding cuts nationwide as Pittsburgh universities join legal challenge [90.5 WESA]" Slides 14/15. Long emails from Pitt officials (chancellor, vice chancellors, etc.) stressing things like "much is at stake with the proposed cuts to indirect costs...A significant reduction of these funds will result in irreparable harm for University operations"

There’s an activation energy barrier to prepping a new mini-lesson on an unfamiliar topic on short notice, so happy to share my slides with others who might be considering doing this in their classroom too. 4/4

Slide 8: Biomedical research cost a lot of money $$$. Why do we need to spend money on for research to get done? Slide 9: Infographic of a lab w/ examples of direct (e.g. salaries, project supplies) and indirect costs (e.g. support personnel, reg compliance, core facilities, libraries, utilities, data storage, waste disposal, etc) highlighted. Slide 10: For every $1 NIH sends directly to a Pitt lab, it also sends up to 59¢ to Pitt to reimburse indirect costs. This rate reflects that many costs of research done at Pitt can’t be budgeted into a single project. What % of the light bill should be charged to each NIH grant? Slide 11: “The indirect rate at Pitt is 59%” Most people hear: “Pitt takes a 59% cut from grants! Only 41% of money actually goes to researchers!” Reality: Let’s say Lab X gets $1 million grant for direct costs. $400K exempt from reimbursement. Pitt gets reimbursed: 0.59 x $600k = $354k Total NIH spends: $1,354,000. % of NIH $ that went toward Pitt overhead = 26%

I was nervous I would miss something (e.g. what the heck is going on with the DEI EO? Did I explain indirects right? Has the situation changed again?) but ultimately decided that if I—a PhD scientist whose training was funded by federal grant $—was confused, it must be way worse for my students. 3/4

Slides 5/6: Grants are peer reviewed and scored by other scientists. In the past few weeks, many grant reviews were abruptly cancelled to comply with executive orders and almost no new grants were approved. The NIH has been directed to resume grant payments, but whether that is happening (or to what extent) is unclear. Existing study sections have resumed, but unclear if new ones can be scheduled. To the right, an infographic shows grant submission and review process with red Xs and/or question marks over affected steps Slide 7: Unis and the gov't share the major costs of research. Graph shows percent of funding coming from different sources since 1970. Federal support is the highest % and has gone down over time. Uni support is second and has risen over time. Slide 8: Pitt is a hub of biomedical research and ranks 6th in most NIH funding. Graph shows funding levels of top 10 institutions. Stock photos of Pitt research including one of Jonas Salk.

I focused my slides on why research matters to my physiology students (mostly bioscience majors pursuing health professions) and how the recent changes impact Pitt. 2/4

Slide 1: Explanation of current events impacting scientific research at Pitt and elsewhere Slide 2: Biomedical research is the foundation of scientific and medical knowledge. Just like understanding insurance is necessary in the education of medical doctors, understanding the basic economics of research is necessary in the education of scientists like YOU! Slide 3: Before WWII, federally-funded research was done in small govt laboratories. Pic: 3 labs & US capitol building w/ thought bubble: "WAY more R&D would be good for the US…Is there an easier way to do this on a bigger scale?" Slide 4: After WWII, US govt funded academic research at universities through grants. Scientists write grants to propose research projects. Researchers must explain what they plan to do, how they plan to do it, why it is worth doing, why it’s likely to succeed, etc. The gov’t funds projects that supports US research priorities (broadly speaking) but most of the work gets done at unis, not all in govt labs.

One perk of being a teaching prof is not needing to worry about the NIH grants…or so I thought. Took 10 mins at the start of class today to teach a crash course on biomedical research funding in the US. Many students said they were confused about what they've been hearing in the news. 1/4

Yes, will do!

YouTube video by mcbfollies Kiwi Blot (MCB Follies 2019)

youtu.be/7cRlE2FkRQk?... one step ahead of ya

Hello, Bluesky! 🌟 We're thrilled to join this community and share the latest in #BER and #DBER research, events, and more. Let’s connect!

Yeah from what I gather the “value” added is
1. look cool by sequencing even the parts of the genome that are irrelevant to their analysis
2. indemnity against criticism because the CEO is a woman under patriarchy so she can’t possibly be critiqued in good faith
3. sleek results printout