A Developmentally Regulated Splice Variant from the Complexlola Locus Encoding Multiple Different Zinc Finger Domain Proteins Interacts with the Chromosomal Kinase JIL-1*

Abstract

Using a yeast two-hybrid screen we have identified a novel isoform of the lola locus, Lola zf5, that interacts with the chromosomal kinase JIL-1. We characterized thelola locus and provide evidence that it is a complex locus from which at least 17 different splice variants are likely to be generated. Fifteen of these each have a different zinc finger domain, whereas two are without. This potential for expression of multiple gene products suggests that they serve diverse functional roles in different developmental contexts. By Northern and Western blot analyses we demonstrate that the expression of Lola zf5 is developmentally regulated and that it is restricted to early embryogenesis. Immunocytochemical labeling with a Lola zf5-specific antibody of Drosophila embryos indicates that Lola zf5 is localized to nuclei. Furthermore, by creating double-mutant flies we show that a reduction of Lola protein levels resulting from mutations in the lola locus acts as a dominant modifier of a hypomorphic JIL-1 allele leading to an increase in embryonic viability. Thus, genetic interaction assays provide direct evidence that gene products from the lola locus function within the same pathway as the chromosomal kinase JIL-1.