#macromere
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evodevopanam.bsky.social
@neva-meyer.bsky.social on behalf of @johnnyds.bsky.social is talking about the evolutionary and developmental origins of CNS in annelid worms #PASEDB2025 #spiralia #micromere #macromere
July 24, 2025 at 1:44 PM
devbiol.bsky.social
#DBfeature 🐌

Serotonin-receptor antagonist treatment disrupts typical asymmetric cleavage in mud snail I. obsoleta embryos, suggesting a novel role for serotonin signalling

By Ayaki Nakamoto, Lisa Nagy

tinyurl.com/bpaexdsw
Early asymmetric cleavage and distribution of serotonin in early Ilyanassa embryos. (A) Schematic figures of the first three asymmetric macromere divisions (4, 8, and 12-cell stages) of the Ilyanassa embryo. Four macromeres are generated during the first two division cycles. During each successive cleavage cycle, each macromere undergoes an asymmetric division and produces a smaller daughter cell (micromere) with a distinct cell fate. The macromeres divide at an oblique angle, clockwise from the animal-vegetal axis, and generate the first micromere daughter cells. In the next cleavage, macromeres divide at a similar oblique angle, counterclockwise from the animal-vegetal axis, and generate the second micromere daughter cells. (B-D′) Serotonin distribution during the 4-cell stage. Co-staining with serotonin (red) and β-tubulin (green) antibodies and DAPI-stained DNA (blue) is shown. During interphase serotonin was detected in the center of the array of microtubules (arrowheads) and the macromere cortex. During prometaphase, an apical section shows that serotonin is concentrated in the apical cytoplasm (C, arrowhead). During metaphase, serotonin is localized to the surface of the macromere and concentrated around the apical spindle pole.
April 8, 2026 at 12:23 PM
tsubasa-rsrch.bsky.social
[3/5] Mesomere_an1 (top、 animal)/ Mesomere_an2 / Macromere / Micromere (bottom、 vegetal)。 🟦 ectoderm precursor (Pmar1=0, HesC high, zβcat=0)
🟠 vegetal-tier (Pmar1 high, zβcat high, Wnt8 feedback)
🟡 transition / ⬜ undifferentiated
May 13, 2026 at 10:26 PM
tsubasa-rsrch.bsky.social
[5/6] Phase 0.5 真の完成 biology truth:
- Micromere = skeletogenic (Pmar1 high + zβcat 102 Wnt8 self-amp)
- Macromere = vegetal-tier endoderm (Foxa 7.04 dominant)
- Mesomere = ectoderm (HesC 93 active、 zβcat 0、 Foxa 2.18 low)
May 13, 2026 at 10:58 PM
tsubasa-rsrch.bsky.social
[2/6] Check 1 Pmar1-HesC double negative gate ✅ (Oliveri 2002+Revilla 2007+Oliveri 2008)
Check 2 Delta-Notch spatial signaling ✅ (Macromere NICD active、 Mesomere off)
Check 3 Foxa/Gatae/Otx endoderm Macromere-dominant ✅ Lv6 BOSS battle 6 structural fix + BUG fix:
1.
May 13, 2026 at 10:58 PM
tsubasa-rsrch.bsky.social
- Mesomere = ectoderm precursor (zβcat 0、 Pmar1 0、 HesC active)
- Micromere/Macromere = vegetal-tier (zβcat 102、 Wnt8 paracrine feedback)
- Pmar1-HesC double negative gate 機能 (Oliveri 2002 + Revilla 2007 + Oliveri 2008)
- Wnt8 micromere-restricted 完全体現 (Wikramanayake 2004 PDF verbatim)
- spatia
May 13, 2026 at 9:58 PM