Isolation and characterization of the Drosophila nuclear envelope otefin cDNA.

We have recently identified and characterized a 53-kDa inner nuclear membrane-associated protein in Drosophila and termed it otefin. Here we report the isolation and characterization of cDNA and genomic clones of the otefin gene. Based on sequence analysis, we deduced that the primary translation product has a calculated mass of 45 kDa, contains many serine and threonine residues, and is mostly hydrophilic. However, in the carboxyl terminus, there is a hydrophobic region which may serve as a membrane anchoring domain. RNA blot analysis indicated that the otefin gene codes for a single poly(A+) transcript of 1.6 kilobases and that relatively large amounts of this transcript are present during developmental stages in which many nuclear divisions occur. Polyclonal antibodies raised against the cDNA translation product react with a 58-kDa mammalian nuclear envelope protein, demonstrating evolutionary conservation.