QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online 16 May 2007
doi: 10.1242/dev.02856

This Article Summary Full Text Full Text (PDF) Supplementary Material Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shravage, B. V. Articles by Roth, S. Search for Related Content PubMed PubMed Citation Articles by Shravage, B. V. Articles by Roth, S.

The role of Dpp and its inhibitors during eggshell patterning in Drosophila

Institute of Developmental Biology, University of Cologne, Gyrhofstr.17, D-50931, Germany.

View larger version (97K): [in this window] [in a new window]   Fig. 1. Grk requires Dpp to induce DV eggshell polarity. Anterior is to the left. (A-C) Double immunofluorescence stainings for Grk (green) and pMAD (red). (A,B) Lateral views. (C) Dorsal view. (D-F) Double immunofluorescence stainings for Grk (green) and ß-gal (red) of the egg chambers dissected from females carrying a dad-lacZ transgene. (D) Dorsal view. (E,F) Lateral views. (G,K) Immunofluorescence stainings for BR-C protein or Fas3 protein in wt stage 10B egg chambers; dorsal views. The white arrowheads mark the dorsal midline (DM). (H-J; L-N) Double immunofluorescence stainings for BR-C (red) or Fas3 (red) and GFP (green) in egg chambers carrying large Med13 mutant follicle cell clones; dorsal views. White lines mark the clone boundaries. White arrows in H mark single wt cells surrounded by cells mutant for Med13. (O) Immunofluorescence staining for ß-gal (red) of the egg chambers dissected from females carrying a pipe-lacZ transgene; lateral view. The white arrowhead marks the DM. (P-R) Double immunofluorescence stainings for ß-gal (red) to detect pipe-lacZ and GFP (green) in egg chambers carrying large Med13 mutant follicle cell clones; lateral views. White lines mark the clone boundaries. (S-U) Darkfield micrographs of deposited eggs. (S) Wild-type egg. (T) Egg laid by female mutant for cap-n-collar (cnc) lacks DV eggshell polarity. In cnc mutants the oocyte nucleus is not anchored at the dorsal-anterior cortex of the oocyte. This prevents the induction of DV polarity by the second round of Grk signaling (Guichet et al., 2001). (U) Egg laid by female in which follicle cell clones mutant for Med13 were induced also lacks DV eggshell polarity.

View larger version (99K): [in this window] [in a new window]   Fig. 2. Dpp is required for the anterior-most part of the operculum in the absence of Grk signaling. Anterior is to the left. (A,D,G) DIC micrographs of anterior eggshell regions. (B,E,H) SEM micrographs of anterior eggshell regions. (C,F,I,K) Stage 14 egg chambers stained for DAPI (blue) and Fas3 (operculum cells, red). (A-C) Wild-type. The operculum can be subdivided into three different regions (I, II, III). The white arrow marks the collar. (D-F) grkHF/grk2B6 eggs have region I operculum cells surrounding the micropyle (yellow arrow) and stage 14 chambers show corresponding Fas3 expression. (G-I) In eggs from females carrying large Med mutant follicle cell clones the region surrounding the micropyle (yellow arrow) is reduced in size and lacks follicle cell imprints. (I) Med13 mutant follicle cell clones in a stage 14 egg chamber lack Fas3 expression. White lines mark the clone boundaries. The inset shows a DIC micrograph of the same egg demonstrating the integrity of the follicular epithelium at the anterior pole. Med13 mutant cell clones showed reduced levels of DAPI staining in later egg chambers. However, the integrity of the follicular epithelium was not affected. (J,K) Eggs and egg chamber from females misexpressing dpp in a grkHF/grk2B6 background. (J) Darkfield micrograph of non-deposited egg (stage 15). Inset shows a DIC image of the abnormally thickened micropyle. (K) Stage 14 egg chamber. Fas3 expression is also found in random patches in more central positions of the main body follicle cells (marked by yellow arrow).

View larger version (86K): [in this window] [in a new window]   Fig. 3. Combined misexpression of Dpp and Grk transforms all mainbody follicle cells into dorsal follicle cells. Anterior is to the left. (A-D) Lateral views of stage 10 egg chambers. (A-C) Double immunofluorescence staining for Grk (green) and pMAD (red). (D) Immunofluorescence stainings for pMAD. (A) Moderate misexpression of dpp (UASdpp x GR1-Gal4). (B) Strong misexpression of dpp (UASdpp x CY2-Gal4). (C) Strong misexpression of grk (UASpgrk x tub-Gal4VP16). (D) Simultaneous strong misexpression of grk (UASpgrk x tub-Gal4VP16) and dpp (UASdpp x CY2-Gal4). (Ea-Ja) Lateral view of darkfield micrographs of deposited eggs. (Eb-Jb) Immunofluorescence stainings for Fas3 (red) and DAPI (blue) of stage 10B egg chambers. Dorsal views, except in Gb, which shows a lateral view. (Ec-Jc) RNA in situ hybridization for BR-C on stage 10B egg chambers (dorsal view). (Ed-Jd) RNA in situ hybridization for kek on stage 10A egg chambers (lateral view) (Ea-d) Wild-type. (Fa-d) Moderate misexpression of dpp (UASdpp x GR1-Gal4). (Ga-d) Strong misexpression of dpp (UASdpp x CY2-Gal4). (Ha-d) Strong misexpression of grk (UASpgrk x tub-Gal4VP16). (Ia-d) Strong misexpression of grk and moderate misexpression of dpp. (Ja-d) Strong misexpression of both grk and dpp.

View larger version (79K): [in this window] [in a new window]   Fig. 4. Expression of dSno in ovaries and functional analysis of dSno and brk. Anterior is to the left. (A-C) RNA in situ hybridization for dSno. (A) Germarium and stage 1 to 4 egg chambers. (B) Lateral and (C) dorsal view of stage 10B egg chambers. (D-F) Double immunofluorescence for ß-gal (red) and BR-C (green). dSno-lacZ is expressed at both lateral and posterior boundaries of the BR-C domain at stage 10B. (G-I) Dorsal view of darkfield micrographs of deposited eggs. (J-L) Lateral view of darkfield micrographs of deposited eggs. White lines serve to measure the operculum size. (M-O) Lateral view of stage 14 egg chambers stained for DAPI (blue) and Fas3 (red). (G,J,M) Wild-type. (H,K,N) dSno174/dSno174. (I,L,O) Overexpression of dSno (UASdSno x CY2-Gal4). (P) Egg from female carrying large brkM68 mutant follicle cell clones. The DAs are replaced by an enlarged operculum. (Q,R) Double immunofluorescence stainings for Fas3 (red) and GFP (green) in a stage 10B egg chamber carrying a large dorsally located brkM68 mutant follicle cell clone.

View larger version (46K): [in this window] [in a new window]   Fig. 5. Regulation of Dpp inhibitors by Grk and Dpp signaling. Anterior is to the left. Lateral view of stage 10B egg chambers. Only the posterior half of the egg chambers is shown. (A,C,E,G,I,K,M) RNA in situ hybridization for dSno. (B,D,F,H,J,L,N) RNA in situ hybridization for brk. The same genotypes are used as in Fig. 3. (A,B) Wild type. (C,D) Moderate misexpression of dpp. (E,F) Strong misexpression of dpp. (G,H) Strong misexpression of grk. Inset in H shows the shift of brk expression to the ventral follicle cells in moderate misexpression of grk. (I,J) Strong misexpression of grk and moderate misexpression of dpp. (K,L) Strong misexpression of grk and dpp. (M,N) grkHF/grk2B6. (O,P) Double immunofluorescence for ß-gal (red) and GFP (green). dSno expression (dSno-lacZ) is downregulated cell autonomously in Med13 mutant follicle cell clones. White lines mark the clone boundaries.

View larger version (62K): [in this window] [in a new window]   Fig. 6. dSno, dad and brk function redundantly in the follicular epithelium to inhibit Dpp signaling. Anterior is to the left. (A,C,E,G,I,K) Dorsal views of darkfield micrographs of deposited eggs. (B,D,F,H,J,L) Dorsal views of stage 10B egg chambers showing BR-C expression. (A,B) Wild type. (C,D) dSno174/dSno174. (E,F) dad(sl)/dad(sl). (G,H) dSno174/dSno174; dad(sl)/dad(sl). (I,J). brkM68/+. (K,L) brk M68/+; dSno174/dSno174.

View larger version (23K): [in this window] [in a new window]   Fig. 7. Schematic representation of the signaling gradients and the expression domains of inhibitors involved in dorsal eggshell patterning.