well as other lymphomas it has been found that three species of mrna are transcribed from the bcl 2 gene at least two different protein products have been identified a 239 amino acid protein designated bcl 2 alpha is translated from a 5 5 kb mrna a protein of 205 amino acids bcl 2 beta is translated from a 3 5 kb mrna it is thought that bcl 2 alpha is also translated from the 8 5 kb mrna species all three size species of transcript share substantial sequence homology in the 5 39 portion of the gene termed the first exon or 5 39 exon the larger two transcripts appear to be spliced to a second exon which is at least 50 kb distal to the first the splice site is in the midst of the protein coding sequence thus the 3 5 kb transcript codes for a protein having a different carboxyl terminus than the proteins coded by the two larger sized transcripts the hotspot for chomosome break points among the t 14 18 translocations of follicular lymphomas map 3 39 to the protein coding region therefore it has now been found that the translocations do not alter the primary structure of the protein products bacterial isolates available from the atcc.