Drosophila melanogasterp24 genes have developmental, tissue‐specific, and sex‐specific expression patterns and functions

Abstract

Genes encoding members of the p24 family of intracellular trafficking proteins are present throughout animal and plant lineages. However, very little is known about p24 developmental, spatial, or sex-specific expression patterns or how localized expression affects function. We investigated these problems in Drosophila melanogaster, which contains nine genes encoding p24 proteins. One of these genes, logjam (loj), is expressed in the adult female nervous system and ovaries and is essential for oviposition. Nervous system-specific expression of loj, but not ovary-specific expression, rescues the behavioral defect of mutants. The Loj protein localizes to punctate structures in the cellular cytoplasm. These structures colocalize with a marker specific to the intermediate compartment and cis-Golgi, consistent with experimental evidence from other systems suggesting that p24 proteins function in intracellular transport between the endoplasmic reticulum and Golgi. Our findings reveal that Drosophila p24 transcripts are developmentally and tissue-specifically expressed. CG31787 is male-specifically expressed gene that is present during the larval, pupal, and adult stages. Female CG9053 mRNA is limited to the head, whereas males express this gene widely. Together, our studies provide experimental evidence indicating that some p24 genes have sex-specific expression patterns and tissue-and sex-limited functions. Developmental Dynamics 236:544 -555, 2007.

Drosophila melanogaster p24 trafficking proteins have vital roles in development and reproduction

“…The putative coiled-coil region of the p24 proteins allows intermolecular interactions between closely related p24 proteins as well as between members of different subfamilies, suggesting the possibility that these proteins function in heteromeric complexes (Fü llekrug et al, 1999;Jenne et al, 2002;Marzioch et al, 1999). This hypothesis is supported by mRNA and protein (current study) expression of p24 family members in the same tissues during different developmental stages (Boltz et al, 2007). Further evidence of protein complexes containing more than one p24 protein comes from experiments in mammalian cells or yeast where reducing levels of a single p24 decreased expression of other endogenous p24s (Belden and Barlowe, 1996;Denzel et al, 2000;Marzioch et al, 1999;Vetrivel et al, 2007).…”

“…Drosophila p24 transcripts show a variety of spatial, temporal and tissue-specific expression patterns and are expressed throughout development and in adults (Boltz et al, 2007;Chintapalli et al, 2007;Celniker et al, 2009). In order to examine protein expression patterns of various p24s, antisera targeting specific members of the Drosophila p24 family were generated (see Section 4.3).…”

“…1H). An antibody that specifically recognizes the LOJ protein was described previously (Boltz et al, 2007).…”

“…Most p24 proteins share similar motifs and topology: an N-terminal GOLD (Golgi dynamics) domain that extends into the vesicle lumen, a second luminal region containing heptad repeats of hydrophobic amino acids which form a coiled-coil domain, a vesicle membrane-spanning region, and an approximately 12-18 amino acid C-terminus that extends into the cell cytoplasm (Carney and Bowen, 2004). One notable exception is Drosophila p24-2 (formerly known as CG33105), which has an extended cytoplasmic region that is approximately 21-28 amino acids longer than that of other p24s (Boltz et al, 2007).…”

Buffering of Genetic Regulatory Networks inDrosophila melanogaster

“…Kank, a gene that affects muscle tendon development, has been shown to be differentially expressed downstream of dsx (Lebo et al 2009), suggesting AI regulation in the sex determination pathway in virgins only. p24-1 has sex-specific expression (Boltz et al 2007) and has been shown to play a role in the neural signaling involved in female egglaying defects and reproductive behavior (Saleem et al 2012). In addition, zCOP is involved in lipid storage and regulation of lipid droplets (Guo et al 2008b) consistent with regulatory changes in lipid metabolism after mating in the fruit fly.…”