14-3-3ε Is Required for Germ Cell Migration in Drosophila

Abstract

Although 14-3-3 proteins participate in multiple biological processes, isoform-specific specialized functions, as well as functional redundancy are emerging with tissue and developmental stage-specificity. Accordingly, the two 14-3-3ε proteins in Drosophila exhibit functional specificity and redundancy. Homozygotes for loss of function alleles of D14-3-3ε contain significantly fewer germ line cells (pole cells) in their gonads, a phenotype not shared by mutants in the other 14-3-3 gene leo. We show that although D14-3-3ε is enriched within pole cells it is required in mesodermal somatic gonad precursor cells which guide pole cells in their migration through the mesoderm and coalesce with them to form the embryonic gonad. Loss of D14-3-3ε results in defective pole cell migration, reduced pole cell number. We present evidence that D14-3-3ε loss results in reduction or loss of the transcription factor Zfh-1, one of the main regulatory molecules of the pole cell migration, from the somatic gonad precursor cells.

Interkingdom Complementation Reveals Structural Conservation and Functional Divergence of 14-3-3 Proteins

“…D14-3-3ε is present in all Drosophila developmental stages and tissues tested [17], [25] and at least for the gonads, it is co-expressed with DmTTLL3A [35], [36]. At least DmTTLL3A should be co-expressed with 6xHis-g14-3-3 under the ubiquitous TubGal4 driver [36]. It is likely then that the sequence recognized on g14-3-3 and D14-3-3ε by gTTLL3 is not a polyglycylation site for the Drosophila enzymes.…”

GAGA protein is essential for male germ cell development in Drosophila

“…Germ cell transcription, including that of the Trl gene, is activated just prior to the start of this stage, and an increase in GAF activity in PGCs at stage 8 has been detected by anti‐GAGA antibodies. The Trl mutant phenotype in this stage is similar to the stat92E, tre‐1, zfh‐1 , and D14‐3‐3ε mutants (Broihier et al ., ; Kunwar et al ., ; Li et al ., ; Tsigkari et al ., ). However, almost all of the described mutant phenotypes result from abnormal expression of the maternal genes.…”

“…However, almost all of the described mutant phenotypes result from abnormal expression of the maternal genes. Only in the D14-3-3e mutant it has been shown that embryonic migration depends on both maternal and zygotic expression (Tsigkari et al, 2012). According to modENCODE data, GAGA sites exist in the regulatory regions of the D14-3-3e gene.…”

The 14-3-3 (YWHA) Proteins in Signalling and Development of the Fruit Fly, Drosophila melanogaster

“…Protein 14-3-3ε has been noticed to be crucial to cellular metabolism by means of molecular crosstalk with ecdysone receptor (EcR) or through direct interaction with metabolic binding partners [17]. The 14-3-3ε isoform is essential for germ cell migration in Drosophila [42]. In addition, this isoform of 14-3-3 antagonizes the transcription factor FoxO to control growth, apoptosis and longevity in Drosophila [43].…”