DrosophilaIk2, a member of the IκB kinase family, is required for mRNA localization during oogenesis

Abstract

In both Drosophila and mammals, IB kinases (IKKs) regulate the activity of Rel/NF-B transcription factors by targeting their inhibitory partner proteins, IBs, for degradation. We identified mutations in ik2, the gene that encodes one of two Drosophila IKKs, and found that the gene is essential for viability. During oogenesis, ik2 is required in an NF-B-independent process that is essential for the localization of oskar and gurken mRNAs; as a result, females that lack ik2 in the germline produce embryos that are both bicaudal and ventralized. The abnormal RNA localization in ik2 mutant oocytes can be attributed to defects in the organization of microtubule minus-ends. In addition, both mutant oocytes and mutant escaper adults have abnormalities in the organization of the actin cytoskeleton. These data suggest that this IB kinase has an NF-B-independent role in mRNA localization and helps to link microtubule minus-ends to the oocyte cortex, a novel function of the IKK family.

Drosophila IKK-related kinase Ik2 and Katanin p60-like 1 regulate dendrite pruning of sensory neuron during metamorphosis

“…Although the requirement of Ik2 signaling in dendrite severing may involve DIAP1 downregulation, inactivation of Ik2 function caused a much stronger dendrite severing phenotype than DIAP1 GOF mutation did, suggesting that Ik2 signals might be mediated by pathways other than or in addition to those involving DIAP1 and caspases to trigger dendrite severing in class IV da neurons during dendrite pruning. The function of ik2 is also required in several other developmental processes in Drosophila, including the regulation of F actin dynamics during trachea and bristle morphogenesis, and the organization of cytoskeletons for proper mRNA localization during oogenesis (18,19,21). One common feature in all these developmental processes is the dynamic organization of cytoskeletons.…”

“…2C, D, and G). Third, 2 independent ik2 EMS mutant alleles, ik2 1 and ik2 alice (21), were used in MARCM analyses to examine the role of ik2 during neuronal development in larvae and during dendrite severing in pupae. In larvae, the dendritic morphology of all 4 classes da neurons in ik2 mutant MARCM clones was indistinguishable from that in the wild-type clones.…”

“…The effect of ik2 LOF mutation is therefore much stronger than that of DIAP1 GOF mutation on suppressing dendrite severing, raising the possibility that Ik2 might regulate other cellular processes to mediate dendrite severing in class IV neurons. Since ik2 is known to have an effect on cytoskeletons in other systems (18,19,21), we next examined the microtubule and actin cytoskeletons in class IV da neurons at pupal stages.…”

A transport and retention mechanism for the sustained distal localization of Spn-F-IKKε during Drosophila bristle elongation

“…This was as a result of misannotation in their laboratory stock list. Both alleles are strong loss-of-function alleles with a missense mutation in the kinase domain and show similar phenotypes (Oshima et al, 2006;Shapiro and Anderson, 2006). Therefore, this error does not affect the conclusions of the paper.…”

Drosophila javelin-like encodes a novel microtubule-associated protein and is required for mRNA localization during oogenesis

“…Previously, we and others have shown that mutations in spindle-F (spn-F) and in the Drosophila IKK homologue ik2, affect both egg chamber polarity and bristle development (Abdu et al, 2006;Shapiro and Anderson, 2006). It has been demonstrated that the defects in egg chamber development in spn-F and ik2 are attributed to their effect on mRNA localization by regulating oocyte cytoskeleton organization.…”