Disease relevance of exu

• In addition, we find that a smaller deletion which removes only sequence within the male 3'-UTR reduces the steady-state level of the mRNA and prevents an exu transgene from rescuing male sterility [1].

High impact information on exu

• Drosophila bicoid mRNA is synthesized in the nurse cells and transported to the oocyte where microtubules and Exuperantia protein mediate localization to the anterior pole [2].
• Here we express a chimaeric gene encoding a fusion between the Acquorea victoria green fluorescent protein (GFP) and the exu protein (Exu) in female germ cells, and find that the fusion protein fluoresces strongly in both live and fixed cells during Drosophila oogenesis [3].
• Furthermore, both Exu/Yps particles and osk mRNA follow a similar temporal pattern of localization in which they transiently accumulate at the oocyte anterior and subsequently localize to the posterior pole [4].
• One of these proteins was identified as the cold shock domain RNA-binding protein Ypsilon Schachtel (Yps), which we show binds directly to Exu and colocalizes with Exu in both the oocyte and nurse cells of the Drosophila egg chamber [4].
• We discovered that exu-null mutants are defective in osk mRNA localization in both nurse cells and the oocyte [4].

Biological context of exu

• Implications for bcd mRNA localization from spatial distribution of exu protein in Drosophila oogenesis [3].
• Our results suggest that exu is not required for the maintenance of bcd mRNA localization during late stages of oogenesis and early embryogenesis, but rather for the establishment of bcd mRNA localization in the developing oocyte [5].
• Interestingly, exu mutants in which Exu phosphorylation is specifically affected can to some extent recover from these bicoid mRNA localisation defects during late oogenesis [6].
• We have extended the characterization of the exu phenotype and find that the gene functions in the male as well as the female germline [7].
• Six of seven exu alleles are male-sterile; mutant defects in spermatogenesis first appear during meiosis [7].

Anatomical context of exu

• This localization does not require Exu, but depends on intact microtubules [8].
• In this work, the structural differences between these sex-specific exu mRNAs were determined by sequence analysis of 9 ovary and 10 testis cDNAs [9].

Enzymatic interactions of exu

• Par-1 regulates bicoid mRNA localisation by phosphorylating Exuperantia [6].

Co-localisations of exu

• Notably, we find that exu protein is colocalized with bcd mRNA during the early phase of localization, when bcd mRNA is positioned at the apical regions of the nurse cells [10].

Regulatory relationships of exu

• Sex-specific processing of the Drosophila exuperantia transcript is regulated in male germ cells by the tra-2 gene [9].

Other interactions of exu

• In contrast, clearly nonadditive effects on the ftz pattern were seen when a mutation in a gene of the anterior class (exuperantia) was combined with mutations in posterior class genes [11].
• Using forms of the 3' UTR lacking this RNA recognition redundancy, we reexamine the roles of the swallow, staufen, and exuperantia genes, which are all required for normal bicoid mRNA localization [12].
• We report here that tra-2 is required in male germ cells for efficient male-specific processing of exu RNA; in the absence of tra-2, X/Y males produce a new mRNA which is processed at its 3' end so that it contains sequences normally specific to the female 3' untranslated region [9].

Analytical, diagnostic and therapeutic context of exu

• To gain insight into the mechanism of anterior patterning, we have used time lapse laser scanning confocal microscopy to analyze transport of particles containing a Green Fluorescent Protein-Exu fusion (GFP-Exu), and to directly image microtubule organization in vivo [13].

References