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Bazooka/PAR3 is dispensable for polarity in Drosophila follicular epithelial cells.

Shahab J, Tiwari MD, Honemann-Capito M, Krahn MP, Wodarz A - Biol Open (2015)

Bottom Line: While all these baz alleles display identical phenotypes during embryonic epithelial development, we observe strong discrepancies in the severity and penetrance of polarity defects in the follicular epithelium: polarity is mostly normal in baz(EH747) and baz(XR11) while baz(4) and baz(815) (-8) show loss of polarity, severe multilayering and loss of epithelial integrity throughout the clones.Further analysis reveals that the chromosomes carrying the baz(4) and baz(815-8) alleles may contain additional mutations that enhance the true baz loss-of-function phenotype in the follicular epithelium.This study clearly shows that Baz is dispensable for the regulation of polarity in the follicular epithelium, and that the requirement for key regulators of cell polarity is highly dependent on developmental context and cell type.

View Article: PubMed Central - PubMed

Affiliation: Stammzellbiologie, Institut für Anatomie und Zellbiologie, Georg-August Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.

No MeSH data available.


Related in: MedlinePlus

Schematic representation and sequence characteristics of baz mutant alleles.(A) Schematic representation of Baz protein with the CR1 domain shown in blue, PDZ domains in red and the aPKC binding site in yellow with black arrows indicating the approximate location of the stop codons present in the respective mutant alleles. (B) Table containing sequence details for the different baz mutant alleles. (C) Western Blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747, and FRT19A mutant embryos. Bands at 55 and 40 kDa (white arrows) are observed in baz4 and baz815-8. Faint bands are observed in all baz allele lanes at 170 kDa. (D) Summary of results of Western blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747 with a comparison to predicted protein product mass for each allele.
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f04: Schematic representation and sequence characteristics of baz mutant alleles.(A) Schematic representation of Baz protein with the CR1 domain shown in blue, PDZ domains in red and the aPKC binding site in yellow with black arrows indicating the approximate location of the stop codons present in the respective mutant alleles. (B) Table containing sequence details for the different baz mutant alleles. (C) Western Blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747, and FRT19A mutant embryos. Bands at 55 and 40 kDa (white arrows) are observed in baz4 and baz815-8. Faint bands are observed in all baz allele lanes at 170 kDa. (D) Summary of results of Western blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747 with a comparison to predicted protein product mass for each allele.

Mentions: The baz4 (Wieschaus et al., 1984) and bazEH747 (Eberl and Hilliker, 1988) alleles were generated by Ethyl Methanesulfonate (EMS) mutagenesis, while the baz815-8 (McKim et al., 1996) and bazXR11 (Kuchinke et al., 1998; Ralf Stanewsky, unpublished) alleles were induced by X-ray mutagenesis (Fig. 4A,B). Based on sequencing data for the different baz alleles (Krahn et al., 2010a), we found that the position of the mutagenesis-induced stop codons in the baz4, baz815-8 and bazEH747 alleles predicts that each of these alleles should produce truncated Baz proteins of different lengths (Fig. 4B,D). The bazXR11 allele does not contain any mutation in the coding region, pointing to a mutation in a regulatory element that prevents transcription or translation of the baz locus (Krahn et al., 2010a). Hypothetically, the baz4 allele should generate a 40 kDa protein consisting of the first 374 amino acids of Baz, spanning the Conserved Region 1 (CR1) domain and a large portion of PDZ domain 1, while the baz815-8 allele should produce a 27 kDa truncated protein consisting of the first 253 amino acids, also spanning the CR1 domain (Fig. 4A,B,D). The bazEH747 allele should encode a 5.6 kDa, 51 amino acid fragment of the N-terminal region of Baz and should span only a portion of the CR1 domain (Fig. 4A,B,D).


Bazooka/PAR3 is dispensable for polarity in Drosophila follicular epithelial cells.

Shahab J, Tiwari MD, Honemann-Capito M, Krahn MP, Wodarz A - Biol Open (2015)

Schematic representation and sequence characteristics of baz mutant alleles.(A) Schematic representation of Baz protein with the CR1 domain shown in blue, PDZ domains in red and the aPKC binding site in yellow with black arrows indicating the approximate location of the stop codons present in the respective mutant alleles. (B) Table containing sequence details for the different baz mutant alleles. (C) Western Blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747, and FRT19A mutant embryos. Bands at 55 and 40 kDa (white arrows) are observed in baz4 and baz815-8. Faint bands are observed in all baz allele lanes at 170 kDa. (D) Summary of results of Western blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747 with a comparison to predicted protein product mass for each allele.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400595&req=5

f04: Schematic representation and sequence characteristics of baz mutant alleles.(A) Schematic representation of Baz protein with the CR1 domain shown in blue, PDZ domains in red and the aPKC binding site in yellow with black arrows indicating the approximate location of the stop codons present in the respective mutant alleles. (B) Table containing sequence details for the different baz mutant alleles. (C) Western Blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747, and FRT19A mutant embryos. Bands at 55 and 40 kDa (white arrows) are observed in baz4 and baz815-8. Faint bands are observed in all baz allele lanes at 170 kDa. (D) Summary of results of Western blot analysis of protein extracts from maternal zygotic baz4, baz815-8, bazXR11, bazEH747 with a comparison to predicted protein product mass for each allele.
Mentions: The baz4 (Wieschaus et al., 1984) and bazEH747 (Eberl and Hilliker, 1988) alleles were generated by Ethyl Methanesulfonate (EMS) mutagenesis, while the baz815-8 (McKim et al., 1996) and bazXR11 (Kuchinke et al., 1998; Ralf Stanewsky, unpublished) alleles were induced by X-ray mutagenesis (Fig. 4A,B). Based on sequencing data for the different baz alleles (Krahn et al., 2010a), we found that the position of the mutagenesis-induced stop codons in the baz4, baz815-8 and bazEH747 alleles predicts that each of these alleles should produce truncated Baz proteins of different lengths (Fig. 4B,D). The bazXR11 allele does not contain any mutation in the coding region, pointing to a mutation in a regulatory element that prevents transcription or translation of the baz locus (Krahn et al., 2010a). Hypothetically, the baz4 allele should generate a 40 kDa protein consisting of the first 374 amino acids of Baz, spanning the Conserved Region 1 (CR1) domain and a large portion of PDZ domain 1, while the baz815-8 allele should produce a 27 kDa truncated protein consisting of the first 253 amino acids, also spanning the CR1 domain (Fig. 4A,B,D). The bazEH747 allele should encode a 5.6 kDa, 51 amino acid fragment of the N-terminal region of Baz and should span only a portion of the CR1 domain (Fig. 4A,B,D).

Bottom Line: While all these baz alleles display identical phenotypes during embryonic epithelial development, we observe strong discrepancies in the severity and penetrance of polarity defects in the follicular epithelium: polarity is mostly normal in baz(EH747) and baz(XR11) while baz(4) and baz(815) (-8) show loss of polarity, severe multilayering and loss of epithelial integrity throughout the clones.Further analysis reveals that the chromosomes carrying the baz(4) and baz(815-8) alleles may contain additional mutations that enhance the true baz loss-of-function phenotype in the follicular epithelium.This study clearly shows that Baz is dispensable for the regulation of polarity in the follicular epithelium, and that the requirement for key regulators of cell polarity is highly dependent on developmental context and cell type.

View Article: PubMed Central - PubMed

Affiliation: Stammzellbiologie, Institut für Anatomie und Zellbiologie, Georg-August Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.

No MeSH data available.


Related in: MedlinePlus