Combined Automated Annotation using Multiple IEA Methods

A screen for genes expressed in the olfactory organs of Drosophila melanogaster identifies genes involved in olfactory behaviour.

Gene-trap line BG00076 (pGT insertion in the SKIP 5' UTR) has reduced olfactory trap responses, and precise excision restores them.

"For BG00076 we found that precise excision of the pGT element in two independent excision lines rescued the olfactory response in both females and males"
The insertion reduces SKIP transcript about five-fold.

"There is an approximately five fold decrease of Skip transcription in line BG00076."
SKIP is expressed in antennae, head and body but not in maxillary palps.

"These experiments showed that the SKIP gene was expressed endogenously in antennae, head, and body but not in four separate preparations of maxillary palp tissue (Figure S4)."

PMID:19463952

Fast inactivation of Shal (K(v)4) K+ channels is regulated by the novel interactor SKIP3 in Drosophila neurons.

SKIP encodes isoforms with SAM and SH3 domains. SKIP1 has SAM1, SH3 and SAM2, SKIP2 has SH3 and SAM2, and SKIP3 has SAM1 only.

"SKIP1 contains both SAM1 and SAM2 domains, while SKIP2 contains only the SAM2 domain and SKIP3 contains only the SAM1 domain."
Shal binding requires the eight C-terminal residues unique to SKIP3, so SKIP3 is proposed to be the only Shal-binding isoform.

"Thus, SKIP3 is likely to be the only SKIP isoform that interacts with Shal channels."
In SKIP-deficient embryonic neurons more cells show very fast-inactivating Shal currents, and myc-SKIP3 expression reverses this.

"We found that myc-SKIP3 expression in ΔSKIP neurons indeed decreased the percentage of neurons with such a rapidly inactivating Shal current to 35%"
Tagged SKIP1 and SKIP3 localize to neuronal cell bodies and to puncta along processes.

"We found that myc-SKIP3 and myc-SKIP1 are localized to neuronal cell bodies and in puncta along neuronal processes (Fig. 3)"
SAM-SAM homo- or heterotypic interactions between SKIP SAM domains were not detected.

"None of these combinations of SAM domains tested positive for an interaction (data not shown)."

file:DROME/SKIP/SKIP-uniprot.txt

UniProt record A0A0B4K6C1 (SKIP, TrEMBL)

file:DROME/SKIP/SKIP-bioinformatics/RESULTS.md

SKIP (FBgn0051163) isoform comparison

The 128-aa product A0A0B4KH49 matches the published SKIP3 architecture. Its unique C-terminal octapeptide, which is needed for Shal binding, is absent from A0A0B4K6C1.

"A0A0B4KH49 is therefore the SKIP3 product, and the Shal-binding octapeptide is absent from A0A0B4K6C1."

file:DROME/SKIP/SKIP-deep-research-manual.md

SKIP manual literature review