Fig. 2

Fig. 2

miR-219 Knockdown Causes Retention of Embryonic Spinal Cord Precursors into Postembryonic Stage

All images show representative transverse sections through trunk spinal cord with dorsal up.

(A–C) In situ hybridization to detect the mature form of miR-219 reveals low expression at 1 dpf but prominent expression at 2 dpf. Staining appears most intense in cells (asterisks) lateral to ventricular zone cells (vz, bracket) lining the primitive lumen. At 3 dpf, miR-219 expression appears uniform in medial spinal cord. Boxed areas are shown in higher magnification in (A2)–(C2).

(D and E) miR-219 (3 dpf) MO-injected larva has more cells that incorporate BrdU than a control larva.

(F) Graph showing the number of BrdU⁺ cells in the ventral, dorsal, and entire spinal cord at 3 dpf. Data represent the mean ± SEM (n = 10 larvae, five to ten sections each). ^****p < 0.0001, unpaired t test.

(G and H) miR-219 (3 dpf) MO-injected larva has more PH3⁺ cells than a control larva.

(I) Graph showing the number of spinal cord cells labeled with anti-PH3 antibody in control and miR-219 MO-injected larvae. Data represent the mean ± SEM (n = 10 sections obtained from 15 larvae per group, with two replicates). p = 0.0328, unpaired t test.

(J–L) miR-219 (3 dpf) MO-injected larvae have more Sox2⁺ cells than control larvae. Graph showing the number of Sox2⁺ cells in ventral, dorsal, and entire spinal cord. Data in graph represent mean ± SEM (n = 10 sections obtained from 15 larvae per group, with three replicates). p = 0.0369, ^****p < 0.0001, unpaired t test. (J, K, M, and N) miR-219 (3 dpf) MO-injected larvae maintain a primitive lumen marked by apically localized F-actin and ZO-1 (brackets). Boxed areas are shown at higher magnification in (J2), (K2), (M2), and (N2). Scale bar equals 10 μm for low-magnification images and 5 µm for high-magnification images.

See also Figure S1.