Fig. 1.   (A) The sequence represented by AB011120 has been mapped to 20p13 (8), falling between the sequence-tagged site (STS) markers D20S113 and D20S97 that define a region of approximately 3 Mb at a distance of 6-9 Mb from the telomere. Known genes mapped to this region include small nuclear ribonucleoprotein polypeptide B/B1 (SNRPB), transglutaminase 3 (TGM3), and cell division cycle 25B phosphatase (CDC25hu2). The BAC clones identified as containing attractin exons map within a 1-Mb region 8-9 Mb from the telomere (white bar). (B) Representation of the exons coding for the 3' ends of soluble attractin (exons 22-25) and membrane attractin (exons 22-24 and 26-30). Exon size is presented in base pairs; numbers in parentheses represent size of noncoding sequence. Intron size (kb) was determined by PCR amplification, and in some instances, confirmed by direct genomic sequencing. The thin shaded bars below represent the PCR-amplified regions used to determine relative expression of soluble and membrane mRNA, and the numbers above each bar represent the size of the amplified fragments.