DEV01527 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure 1 -

  Fig. S1. Schematic representation of tendon precursor position during leg disc eversion at 8, 25 and 35 hours APF. Tendons of the tarsus, tibia and femur are labeled by green lines, with annotations a, b, c, d and g. The blue arrow marks the direction of disc eversion; the black arrows indicate the progressive formation of the tibia/femur junction. Note the morphogenetic changes within the area of the femur/tibia junction.

• Supplemental Figure 2 -

  Fig. S2. Muscles and tendons of coxa and trochanter. (A) Anterior and (C) posterior views of a MHC-tauGFP 55-hour APF pupae, revealing coxa and trochanter muscles. (B) GFP-expressing tendons of coxa and trochanter from a Stripe-GAL4/UAS-GFP 55-hour APF pupae. (D) Femur depressor muscle (fedm) from a MHC-tauGFP 60-hour APF pupae. (E-I) Dissected coxa muscles from (E) MHC-tauGFP/1151-DsRED and (F-I) MHC-tauGFP adult flies. (E) General view of dissected trochanter levator and depressor muscles and tendons. (F) Fibres of trochanter depressor muscle (trdm) with the nuclei arranged in two rows. Enlarged views of (G) the trochanter reductor muscle fibres (trrm) and (H) the levator muscle fibres (clm). The nuclei are revealed by PI staining (red). (I) Comparison of the trochanter levator (trlm) and depressor (trdm) muscle fibres, showing the differences in sarcomeric MHC-tauGFP accumulation in these two muscle types.

• Supplemental Figure 3 -

  Fig. S3. Sarcomeres and ultrastructure of leg muscle fibres. (A-C) Transmitted light views of dissected tibia muscle fibre, (A) tirm, (B) tilm and (C) tidm, showing different sizes of sarcomeres (S) depending on the fibre type; measuring 4.0 (tirm), 3.5 (tilm) and 2.5 mm (tidm), respectively (compare the lengths of the white lines). (D) Schematic of sarcomere structure. The thick and thin black lines represent thick and thin filaments, respectively. Allocation of Z, I, H and M bands of the sarcomere with respect to the transmitted light view of a tidm sarcomere is presented. (E-I) Ultrastructure of the tibia levator (tilm) and depressor (tidm) muscle fibres revealed by the electron microscopy. (E,F) Longitudinal and (G) transverse section through a tilm fibre. (E,F) High magnification images of a tilm fibre, showing numerous mitochondria (black arrowheads) accumulated close to the Z bands (white arrow) and intermingled between myofibrils (MF), or packed immediately under the sarcolemma. (G) Transverse section (inset show the same image at a higher magnification) through a levator muscle fibre, revealing a ‘ rosette-like’ organisation of myofibrils (MF) with centrally and peripherally located mitochondria (Mt). Black arrows indicate nuclei. (H,I) High magnification images of a tidm fibre, showing a low number of intrasarcomeric and peripherally located mitochondria (black arrowheads). White arrows indicate the Z bands. (J) Schematic representation of a transverse section through a muscle fibre, showing the general organisation of myofibrils (MF), and the respective location of nuclei (N) and mitochondria (Mt). Note different number and location of mitochondria in the levator (E,F) versus depressor (H,I) fibres. Muscle and tendon names and abbreviations are defined in Table 1.