Genomic cloning of inv(2)(p23q35).

(A) Southern blot hybridization of ALCL tumor DNA from patient 2 usingALK probe 2 (see panel B), demonstrating rearranged restriction fragments (arrowheads). (B) Schematic of a portion of the germlineALK locus, and of the chimeric genomic fragment generated by the inv(2)(p23q35). The exact sizes of the exons encoding the transmembrane (TM) and tyrosine kinase (TK) domains of ALK have not been determined, and are therefore shown as interrupted cross-hatched boxes. The position of the inv(2) genomic breakpoint in the tumor of patient 2 is illustrated. The genomic location of ATIC exons was not determined; however, no exons were identified by sequencing of the approximately 2.0-kb segment of the ATIC locus extending from the XbaI restriction site to the breakpoint location. The location of the primer pair (2q35A, 2q35B) from the 2q35 gene locus used to identify clones PAC213D24 and PAC218E3 by PCR-based library screening is shown. JM, ALK juxtamembrane-encoding exon. (C) FISH analysis of inv(2). FISH of a metaphase chromosome spread from the inv(2)-positive ALCL tumor of patient 1 with PAC213D24, demonstrating its localization to 2q35 on the normal chromosome 2 and i(2)(q10) (which is a secondary chromosomal abnormality seen in inv(2)-positive cases that is formed by the joining of 2 long arms produced by the inversion11), and splitting of the clone by the inv(2)(p23q35).