SHORT COMMUNICATION Cloning and Expression Analysisof a Novel WD Repeat Gene, WDR3, Mapping to 1p12–p13 Jaime O. Claudio,* , † Choong-Chin Liew,‡ Jun Ma,‡ Henry H. Q. Heng,§ A. Keith Stewart,* , † and Robert G. Hawley* ,1 * Oncology Research, University Health Network and †Canadian Blood Services, Toronto Centre, Toronto, Ontario M5G 2M1, Canada; ‡Cardiac Gene Unit, Centre for Cardiovascular Research, University Health Network, Toronto, Ontario M5G 2C4, Canada; and §SeeDNA Biotech Inc., York University, Toronto, Ontario M3J1P3, Canada Received November 23, 1998; accepted April 14, 1999 WD repeat proteins are components of multiprotein complexes that are involved in a wide spectrum of cellular activities, such as cell cycle progression, sig- nal transduction, apoptosis, and gene regulation. These proteins are characterized by repeat units bracketed by Gly-His and Trp-Asp (GH-WD). We report here the isolation of a new member of the WD repeat gene family, WDR3, which encodes a putative 943- amino-acid nuclear protein consisting of 10 WD repeat modules. WDR3 is widely expressed in hematopoietic cell lines and in nonhematopoietic tissues. Fluores- cence in situ hybridization mapped WDR3 to human chromosome 1p12–p13, a region that is affected by chromosomal rearrangements in a number of hemato- logic malignancies and solid tumors. © 1999 Academic Press A conserved core of four or more modular repeat units defines a group of functionally diverse regulatory proteins in eukaryotes known as the WD repeat family (16). WD repeats are minimally conserved regions of approximately 40 amino acids, typically bracketed by Gly-His and Trp-Asp (GH-WD), which may facilitate formation of heterotrimeric or multiprotein complexes. The WD repeat was first identified in the -subunit of the GTP-binding protein transducin (9); hence, it is sometimes referred to as the -transducin repeat. Pro- teins belonging to this family are involved in a variety of cellular processes, including gene regulation (TUP1, Hir1p) (7, 12), cell cycle progression [srw1(+)] (19), development (Groucho) (18), apoptosis (Apaf1,a CED-4 homolog) (3, 20), signal transduction (FAN, RACK1) (1, 13), RNA processing (PRP4) (2), vessicular trafficking (SEC13) (17), cytoskeleton assembly (CDC4) (4), and nucleosome remodeling (NURF-55) (14). We previously reported the generation of over 1000 expressed sequence tags (ESTs) from a ZAP Express cDNA library of the human CD34 + hematopoietic pro- genitor line KG-1a (http://www.tcgu.med.utoronto.ca/ CD34/) (5). Of these KG-1a ESTs, 101 did not match any sequence entry in the nonredundant public data- bases or in dbEST. A further 279 KG-1a ESTs showed sequence similarity either to existing ESTs represent- ing human genes of unknown function or to genes in other species whose human orthologs had not been described. Among the latter dataset, we identified an EST, PMY0992 (GenBank Accession No. AA431069), that exhibited significant sequence similarity to a por- tion of a WD repeat-encoding gene, the yeast transcrip- tional regulator TUP1 (12). We used the 2-kb PMY0992 partial cDNA clone to rescreen the KG-1a cDNA library (5) and isolated three additional ZAP Express phages, two of which had cDNA inserts of approximately 4 kb. The sequence of the full-length cDNA identified by PMY0992 was obtained from these latter clones by cycle sequencing and primer walking (5). The complete consensus coding region of this gene, designated WDR3 (Fig. 1; GenBank Accession No. AF083217), specifies a protein of 943 amino acids. Pro- tein sequence motif searching and pattern matching analysis using a series of Internet-based software programs [PROSITE (http://www.expasy.hcuge.ch/ sprot/prosite.html), BLOCKS (http://www.blocks.fhcrc. org), MotifFinder (http://www.genome.ad.jp/sit-bin/nph), PSORT (http://psort.nibb.ac.jp/cgi-bin) and BlastP (http://www.ncbi.nlm.nih.gov/BLAST)] revealed sev- eral noteworthy structural features. WDR3 is pre- dicted to encode a putative 106-kDa nuclear protein that possesses 10 WD repeat modules. The first 4 WD repeats are separated from the remaining 6 WD re- peats by a consensus nuclear localization signal (resi- dues 311–327). A second nuclear localization signal Sequence data from this article have been deposited with the GenBank/EMBL Data Libraries under Accession No. AF083217. 1 To whom correspondence should be addressed at current address: Hematopoiesis Department, Holland Laboratory, American Red Cross, 15601 Crabbs Branch Way, Rockville, MD 20855. Telephone: (301) 738-0420. Fax: (301) 738-0444. E-mail: hawleyr@usa. redcross.org. All articles available online at http://www.idealibrary.com on Genomics 59, 85– 89 (1999) Article ID geno.1999.5858 85 0888-7543/99 $30.00 Copyright © 1999 by Academic Press All rights of reproduction in any form reserved.