Worm Breeder's Gazette 14(2): 50 (February 1, 1996)

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

ceh-26, a putative prospero (pros) homologue

Rene F. Pretot, Thomas R. Burglin

Biocenter, University of Basel, Switzerland

In Drosophila the homeodomain encoding pros gene has been shown to be required for activation of the homeobox genes even-skipped (eve) and fushi-tarazu (ftz ) in ganglion mother cells (GMCs). During mitosis of the neuroblasts, the protein is segregated in a cortical crescent that becomes part of the resulting GMC. Only in established interphase, pros protein migrates into the nucleus, where it presumably acts as a transcription factor.

The genome project sequenced an open reading frame (K12H4.1, which we call now ceh-26 ) with sequence similarity to pros*. The homeodomain of ceh-26 is atypical, with 3 extra amino acids between helix 2 and helix 3. In addition, there is a conserved domain following the homeodomain (see Fig. 1). Using the open-reading-frame (ORF) predicted by Genefinder, we succeeded in generating cDNAs using PCR. However, sequencing showed various PCR induced point mutations. With these PCR cDNAs, we isolated cDNAs from the Chris Martin and the Pete Okkema libraries. One consistent difference to the sequence from the genome project, an extra base, was found in all cDNAs looked at. Overall, the ORF prediction was confirmed, except for one splice donor. This difference in the splice pattern is necessary to compensate for the extra base to produce the correct ORF.

The cDNAs are now being used to generate fusion proteins. Upon obtaining antibodies, we will be able to determine, whether there is a similar phenomenon of asymmetric protein localization in C. elegans.

Fig. 1

                                        homeodomain
              =======================================   =====================--------------------   
ceh-26    423 GGGSSSMLTPMHLRKAKLMFFYTRYPNSNLLKSYFPDIRFNKNNTAQLVKWFSNFREFYYNQMEKFARQALAEGITDRNDIFV 
                  || ||||||||||||||:.|||.|.:|| |||||:||||||||||||||||||||| ||||:||||:.|||...:|::: 
pros     1245 TPLHSSTLTPMHLRKAKLMFFWVRYPSSAVLKMYFPDIKFNKNNTAQLVKWFSNFREFYYIQMEKYARQAVTEGIKTPDDLLI 

              -------------------pros domain --------------------------------------------------       
ceh-26    506 SKDSELFKVLNTHYNRNNHIKAPDRLVFVVQETLREFHDAIKQGKDIEPSWKKTIYKVINRLEDQIPDFFKEPNFLERLET*  586 
              . ||||::||| ||||||||..|:.: |||:.|||||  ||..|||.|.||||.|||:|.|::|.:|::||.|||||.||          
pros     1328 AGDSELYRVLNLHYNRNNHIEVPQNFRFVVESTLREFFRAIQGGKDTEQSWKKSIYKIISRMDDPVPEYFKSPNFLEQLE* 1407

*) Bürglin, T.B., (1994), TIBS 19, 70

#) René Prétôt