Worm Breeder's Gazette 12(3): 67 (June 15, 1992)
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.
One of the first instances described where a homeobox containing gene was implicated in carcinogenesis, was in the case of pre-B cell leukemias (1&2;). The t(l; 19) translocation causes the production of a chimeric transcript that joins E2 Ato the homeodomain of prl (now named PBX1 ). Using PBX1 as a probe two additional genes were subsequently isolated, PBX2 and PBX33 .These genes share extensive sequence homology throughout their complete sequences to PBX1 . Scanning Ainscough et al.'s list of randomly sequenced C. elegans cDNAs in WBG 12, No 1, we detected one clone ( cm7b 3)which showed homology to PBX1 . We obtained the clone (thanks to Bob Waterston and colleagues) and further sequence analysis revealed that it contained a homeodomain highly related to the PBX genes. This homeobox gene has been named ceh-20 .Like the PBX genes and MAT a2 , ceh-20 has an atypical homeodomain with 3 extra amino acids between helix 1 and helix 2. In addition to the conserved homeodomain, ceh-20 shares extensive sequence similarity to the PBX genes upstream of the homeodomain. Two regions of approximately 80 and 95 amino acids are well conserved, and we term these regions PBC-box A and B (PBX and ceh-20 ).The conservation downstream of the homeodomain extends for about 20 amino acids. We are further investigating ceh-20 to find out what possible role this gene has during C. elegans development.
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