tokens: A combination of differential splicing and alternative use of promoters generates four mRNA isoforms , of 2 . 6 kb and 1 . 3-1 . 5 kb in size .
folded_tokens: a combination of differential splicing and alternative use of promoters generates four mrna isoforms , of 2 . 6 kb and 1 . 3-1 . 5 kb in size .
labels: O O O B-other_name I-other_name O O O O B-DNA_family_or_group O O B-RNA_family_or_group O O O O O O O O O O O O O O O O O