Point mutation in 3′ DNA adjacent to pre–mir-16-1 region in NZB. (A) Nucleotide sequence comparison of the region of mouse chromosome (chr) 14 and human chr 13 on which miRNA mir-16-1 is located. The top sequence is the database reference sequence20 (antisense strand) in Homo sapiens for hsa-mir-16-1 with sense strand base coordinates (NCBI36) 13:49 521 099 to 13:49 521 187 The second sequence is the antisense of the database reference sequence in Mus musculus for mmu-mir-16-1 with the sense strand base coordinates (NCBIM36) 14:60 585 981 to 60 586 067. The sequence homology between the mir-16-1 region (including the 3′ flanking region) of Mus musculus (chr 14) and of Homo sapiens (chr 13) is shown (vertical arrows indicate the end of the pre–mir-16-1 in humans vs mouse). The third and fourth rows are sequence comparisons of splenic DNA from DBA/2J and NZB/BlNJ mice. The sequences are identical to the reference sequence, except for a T → A point mutation (on the antisense strand; A → T point mutation at base 60 585 990 on the sense strand of chr 14) in the NZB/BlNJ. In addition, DNA extracted from DBA/2J (5 weeks old) liver, NZW (5 weeks old) spleen, Balb/C B-cell lymphoma cell line (CH27), C57BL/6 (4 months old) kidney, SJL/J B cell lymphoma line (NJ117), and NOD/SCID (7 months old) liver showed no point mutations, whereas DNA from NZB/BlNJ spleen, liver (14 months old), kidney (15 months old), T-cell lymphoma line (3C2), and malignant B1 cell line (LNC) all had the same point mutation (data not shown). The precursor stem-loop structure sequences (pre-miRNA) are based on established nomenclature.20 In the mouse samples (pre–mmu-mir) for both pre–mir-15a (accession no. MI0000564) and pre–mir-16-1(MI0000565) and mature sequences for both miR-15a (MIMAT0000526) and 16-1 (MIMAT0000527) were also compared, and no other mutation was found in these regions (data not shown). The shaded boxed region is the mature miR-16, and the unshaded boxed region is the 3′ flanking region, which is further compared in panel B. (B) Sequence comparison between human and mouse 3′ adjacent to pre–mir-16-1. The point mutations in NZB/BINJ splenic DNA and in the reported DNA of patients with CLL9 are indicated. The NZB/BINJ splenic DNA shows an A → T mutation at the 60 585 984 base on chromosome 14, which is 6 bases from the end of the mmu-mir-16-1 sequence. CLL DNA has a reported G → A mutation at the 49 521 103 base on chromosome 13, 7 bases from the hsa-mir-16-1 sequence.9
