Descriptive diagram of 4p16, MMSET locus, and MMSET proteins. (A) Representation of the 0.5-Mb region of 4p16.3 from the human genome project Build 34.3 flanking known t(4;14) breakpoints. Arrows indicate the direction of transcription. Empty boxes are predicted genes based on mapped image consortium clones. (B) Exon-intron structure diagram of the MMSET gene. The breakpoint cluster regions for MB4-1, MB4-2, and MB4-3 are shown. Solid lines indicate the proper splicing pattern that leads to the production of the MMSET II mRNA species. Alternative splicing events that produce MMSET III and MMSET I are indicated by dotted gray lines. In-frame stop codons are indicated by asterisks. The proper translation initiation site of MMSET is indicated by a solid black arrow, while the alternative translation initiation sites in exon 4 and 6 identified by MC and PLB¹³  are indicated by gray arrows. The point of transcription initiation of RE-IIBP is indicated by gray square boxes and the translation initiation site is indicated by a dotted black arrow. The approximate locations of the individual qRT-PCR reactions are indicated by dotted black lines. The MMSET total (T) reaction spans exons 8 and 9, while MMSET II spans exons 16 and 17. (C) Conserved domains present in MMSET variants as predicted by SMART protein prediction program.^28,29  Shaded boxes indicate the position of the identified protein domains.