1. The Tec29 Tyrosine Kinase Is Required during Drosophila Embryogenesis and Interacts with Src64 in Ring Canal Development 
Erica M Roulier, Scott Panzer, Steven K Beckendorf 
Molecular Cell 
Volume 1, Issue 6, Pages (May 1998)
DOI: /S (00)

2. Figure 1
During Oogenesis, Egg Chambers Mature as They Move Posteriorly through the Tubular Ovarioles
One ovariole with various stages of egg chambers is depicted here. Cystoblast division occurs at the anterior tip of each ovariole, within region 1 of the germarium, an enlargement of which is shown (adapted fromMahowald and Strassheim 1970). In region 2a, follicle cells begin to surround each 16 cell cyst, with each cyst completely surrounded by region 2b, at which point the cyst is lens-shaped. In region 3 (or stage 1) the cyst has rounded to a spherical shape and is pinched off from the germarium by the follicle cells to become a stage 2 egg chamber. As the egg chamber matures, the 15 nurse cells, located anteriorly to the oocyte, contribute cytoplasmic components to the oocyte through the intercellular bridges, or ring canals. Beginning at stage 10, there is a rapid transfer of cytoplasm from the nurse cells to the oocyte through the fortified intercellular bridges, which increase in size throughout oogenesis. The nurse cells degenerate after completing cytoplasmic transfer, and the eggshell is deposited by the follicle cells to produce a mature (stage 14) oocyte ready to be fertilized.
Molecular Cell 1998 1, DOI: ( /S (00) )

3. Figure 2
Tec29 Sequence, Protein Domain Homologies, and P Element Insertions
(A) 5′ end of the corrected Tec29 sequence, compared to the published sequence (Gregory et al. 1987). Three guanine nucleotide deletions were found, indicated in bold in the published sequence and with (✓) in the corrected sequence. The resulting frameshift is underlined. Note that the new 5′ clone does not extend to the 5′ end of the published clone.
(B) Comparison of predicted amino acid sequences in the Btk motif and proline-rich region of Tec29 and the other Tec family members, Tec, Btk, and Itk (Mano et al. 1990; Siliciano et al. 1992; Tsukada et al. 1993; Vetrie et al. 1993). The Tec29 sequence shown is for the p66 isoform. p55 begins at the methionine just upstream from the proline-rich domain (Gregory et al. 1987).
(C) Homologous regions in Tec29, Tec, and Src. Percent identity between Tec29 and each of the human kinases is indicated above their SH3, SH2, and kinase domains.
(D) Locations of PlacW insertions relative to the first two Tec29 exons.
Molecular Cell 1998 1, DOI: ( /S (00) )

4. Figure 3 Embryonic Tec29 Expression and Phenotype
(A and B) Tec29 transcript is absent in embryos homozygous for either PlacW insertion, as shown by Tec29 in situ hybridization. (A) Tec295610/+ and (B) Tec295610/Tec
(C–F) Cuticle preparations of nonhatching Tec29 mutant embryos lack specific head skeleton structures present in wild-type. Shown are lateral views of wild-type (C) and Tec29 (D) and dorsal views of wild-type (E) and Tec29 (F). Structures that are missing in Tec29 mutants are indicated on the wild-type cuticles. These include the dorsal bridge (1), anterior portions of the vertical plate (2), epistomal sclerite (3), labrum (4), H-piece lateral bar (5), and the posterior portions of the mouth hook (6).
Molecular Cell 1998 1, DOI: ( /S (00) )

5. Figure 4
The Phosphotyrosine Content of Ring Canals Is Greatly Reduced in Tec29 Germline Clones and in Src64 Mutants, and These Ring Canals Do Not Grow to Normal Size
(A) Wild-type ovariole. (B) Ovariole from a Tec29 germline clone. (C) Src64Δ17 ovariole. (D) The Src64Δ17 ring canal phenotype is enhanced by a 2-fold reduction of Tec29. Ovariole shown is from a female with the phenotype Tec29206/+ ; Src64Δ17 hmz. Insets for each panel show an enlargement of the ring canal indicated by the arrow. Phosphotyrosine localization is visualized using the PY20 antibody.
Molecular Cell 1998 1, DOI: ( /S (00) )

6. Figure 5
Actin, Hts, and Kelch are all recruited to ring canals normally in Tec29 germline clones
(A, C, and E) Wild-type egg chambers. (B, D, and F) Egg chambers from Tec29 germline clones. Note here also the reduction in ring canal size, as compared to wild type. (A and B) Actin localization, shown in single confocal sections. (C and D) Hts localization, shown as confocal series projections. (E and F) Kelch localization, shown as confocal series projections.
Molecular Cell 1998 1, DOI: ( /S (00) )

7. Figure 6 Tec29 and Src64 Protein Localization
(A–C) Tec29 protein in wild-type egg chambers. (A) Tec29 localization to ring canals (arrow) is first seen in region 2b of the germarium (a single confocal section is shown). Tec29 is localized to ring canals throughout the remainder of oogenesis. (B) A germarium and several more mature egg chambers within an ovariole. (C) Stage 10 egg chamber.
(D–F) Tec29 protein in Src64Δ17 homozygous egg chambers. (D and E) Tec29 is not localized to ring canals in most Src64 mutant egg chambers, although nurse cell membrane localization is still seen. (F) Src64Δ17 egg chambers are occasionally seen in which Tec29 is nonuniformly localized to a few ring canals.
(G–I) Src64 protein localization. (G) Projection of stage 10 egg chamber showing Src64 localization to ring canals and nurse cell membranes. (H) Single confocal section through a stage 9 wild-type egg chamber. Two ring canals are seen here (arrows). At this stage ring canals are obscured in projections due to the abundance of signal in the cytoplasm. (I) Src64 localization to ring canals (arrows) in a Tec29 mutant egg chamber (confocal section).
Molecular Cell 1998 1, DOI: ( /S (00) )

8. Figure 7
The Ring Canal Development Pathway Involves the Establishment of the Ring Canal Structure Followed by Ring Canal Growth
The establishment phase is depicted in regions 1–3 in the germarium as new components are sequentially recruited to the ring canals as the egg chamber progresses through the germarium. Subsequently, the growth phase, in which the ring canal diameter expands from 1 to 8–10 μm, involves the addition of new actin filaments to the ring canal and possibly the regulated sliding of filament bundles past one another. In this model, we have placed Tec29 and Src64 in a pathway parallel to the ring canal formation pathway, as these kinases do not appear to affect the localization of the other ring canal components. They are, however, both required for ring canal growth. We have placed Tec29 downstream of Src64 because Tec29 localization to the ring canals requires Src64. Our preliminary results suggest that Src64 may be the earliest phosphotyrosine protein on ring canals (see text). However, until this can be proven, we have retained the possibility that the first phosphotyrosine protein is still unidentified.
Molecular Cell 1998 1, DOI: ( /S (00) )