GENOMIC STRUCTURE OF THE HUMAN RBP56 HTAF(II)68 AND FUS/TLS GENES/

We previously isolated RBP56 cDNA by PCR using mixed primers designed from the conserved sequences of the RNA binding domain of FUS/TLS and EWS proteins. RBP56 protein turned out to be hTAF(II)68 which was isol ated as a TATA-binding protein associated factor (TAF) from a sub-popu lation of TFIID complexes (Bertolotti A., Lutz, Y., Heard, D.J., Chamb on, P., Tora, L., 1996. hTAF(II)68, a novel RNA/ssDNA-binding protein with homology to the proto-oncoproteins TLS/FUS and EWS is associated with both TFIID and RNA polymerase II. EMBO J. 15, 5022-5031). The RBP 56/hTAF(II)68, FUS/TLS and EWS proteins comprise a sub-family of RNA b inding proteins, which consist of an N-terminal Ser, Gly, Gin and Tyr- rich region, an RNA binding domain, a Cys(2)/Cys(2) zinc finger motif and a C-terminal RGG-containing region. Rearrangement of the FUS/TLS g ene and the FUS gene has been found in several types of malignant tumo rs, and the resultant fusion proteins play an important role in the pa thogenesis of these tumors. In the present study, we determined the ge nomic structure of the RBP56/hTAF(II)68 gene. The RBP56/hTAF(II)68 gen e spans about 37 kb and consists of 16 exons from 33 bp to 562 bp. The longest exon, exon 15, encodes the C-terminal region containing 19 re peats of a degenerate DR(S)GG(G)YGG sequence. While the structure of t he FUS/TLS gene has been reported previously, we determined the total DNA sequence of the FUS/TLS gene, consisting of 12 kb. The RBP56/hTAF( II)68, FUS/TLS and EWS genes consist of similar numbers of exons. Comp arison of the structures of these three genes showed that the organiza tion of exons in the central part encoding a homologous RNA binding do main and a cysteine finger motif is highly conserved, and other exon b oundaries are also located at similar sites, indicating that these thr ee genes most likely originate from the same ancestor gene. (C) 1998 E lsevier Science B.V. All rights reserved.