title: Alterations in the mir-15a/16-1 Loci Impairs Its Processing and Augments B-1 Expansion in De Novo Mouse Model of Chronic Lymphocytic Leukemia (CLL).
abstract: New Zealand Black (NZB) mice, a de novo model of CLL, share multiple characteristics with CLL patients, including decreased expression of miR-15a/16-1. We previously discovered a point mutation and deletion in the 3' flanking region of mir-16-1 of NZB and a similar mutation has been found in a small number of CLL patients. However, it was unknown whether the mutation is the cause for the reduced miR-15a/16-1 expression and CLL development. Using PCR and in vitro microRNA processing assays, we found that the NZB sequence alterations in the mir-15a/16-1 loci result in deficient processing of the precursor forms of miR-15a/16-1, in particular, we observe impaired conversion of pri-miR-15a/16-1 to pre-miR-15a/16-1. The in vitro data was further supported by derivation of congenic strains with replaced mir-15a/16-1 loci at one or both alleles: NZB congenic mice (NmiR+/-) and DBA congenic mice (DmiR-/-). The level of miR-15a/16-1 reflected the configuration of the mir-15a/16-1 loci with DBA congenic mice (DmiR-/-) showing reduced miR-15a levels compared to homozygous wild-type allele, while the NZB congenic mice (NmiR+/-) showed an increase in miR-15a levels relative to homozygous mutant allele. Similar to Monoclonal B-cell Lymphocytosis (MBL), the precursor stage of the human disease, an overall expansion of the B-1 population was observed in DBA congenic mice (DmiR-/-) relative to wild-type (DmiR+/+). These studies support our hypothesis that the mutations in the mir-15a/16-1 loci are responsible for decreased expression of this regulatory microRNA leading to B-1 expansion and CLL development.
authors.affiliation: New Jersey Medical School, Rutgers University, Newark, New Jersey, 07103, United States of America.
authors.forename: Siddha
authors.initials: S
authors.lastname: Kasar
authors.affiliation: New Jersey Medical School, Rutgers University, Newark, New Jersey, 07103, United States of America.
authors.forename: Chingiz
authors.initials: C
authors.lastname: Underbayev
authors.affiliation: OSEL/CDRH/FDA White Oak, Maryland, United States of America.
authors.forename: Moinuddin
authors.initials: M
authors.lastname: Hassan
authors.affiliation: OSEL/CDRH/FDA White Oak, Maryland, United States of America.
authors.forename: Ilko
authors.initials: I
authors.lastname: Ilev
authors.affiliation: CBER/FDA White Oak, Maryland, United States of America.
authors.forename: Heba
authors.initials: H
authors.lastname: Degheidy
authors.affiliation: CBER/FDA White Oak, Maryland, United States of America.
authors.forename: Steven
authors.initials: S
authors.lastname: Bauer
authors.affiliation: OSEL/CDRH/FDA White Oak, Maryland, United States of America.
authors.forename: Gerald
authors.initials: G
authors.lastname: Marti
authors.affiliation: New Jersey Medical School, Rutgers University, Newark, New Jersey, 07103, United States of America.
authors.forename: Carol
authors.initials: C
authors.lastname: Lutz
authors.affiliation: New Jersey Medical School, Rutgers University, Newark, New Jersey, 07103, United States of America.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Raveche
authors.affiliation: New Jersey Medical School, Rutgers University, Newark, New Jersey, 07103, United States of America.
authors.forename: Mona
authors.initials: M
authors.lastname: Batish
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000473:pathology*; D001483:Base Sequence; D002460:Cell Line; D049109:Cell Proliferation; D004195:Disease Models, Animal; D056426:Genetic Loci; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000473:pathology*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D011506:Proteins / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional; D058985:Side-Population Cells / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013154:Spleen / Q000378:metabolism; D014166:Transferases
chemical_list: D035683:MicroRNAs; C570833:Mirn15 microRNA, mouse; C522604:Mirn16 microRNA, mouse; D011506:Proteins; C486375:Dleu2 protein, mouse; D014166:Transferases