title: Motifs within the CA-repeat-rich region of Surfactant Protein B (SFTPB) intron 4 differentially affect mRNA splicing.
abstract: The first half of the surfactant protein B (SP-B) gene intron 4 is a CA-repeat-rich region that contains 11 motifs. To study the role of this region on SP-B mRNA splicing, minigenes were generated by systematic removal of motifs from either the 5' or 3' end. These were transfected in CHO cells to study their splicing efficiency. The latter was determined as the ratio of completely to incompletely spliced SP-B RNA. Our results indicate that SP-B intron 4 motifs differentially affect splicing. Motifs 8 and 9 significantly enhanced and reduced splicing of intron 4, respectively. RNA mobility shift assays performed with a Motif 8 sequence that contains a CAUCcis-element and cell extracts resulted in a RNA:protein shift that was lost upon mutation of the element. Furthermore,in silicoanalysis of mRNA secondary structure stability for minigenes with and without motif 8 indicated a correlation between mRNA stability and splicing ratio. We conclude that differential loss of specific intron 4 motifs results in one or more of the following: a) altered splicing, b) differences in RNA stability and c) changes in secondary structure. These, in turn, may affect SP-B content in lung health or disease.
authors.affiliation: Center for Host Defense, Inflammation, and Lung Disease (CHILD) Research, Department of Pediatrics, Penn State Hershey College of Medicine, Pennsylvania State University, Hershey, Pennsylvania.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Yang
authors.forename: Lan
authors.initials: L
authors.lastname: Ni
authors.forename: Patricia
authors.initials: P
authors.lastname: Silveyra
authors.forename: Guirong
authors.initials: G
authors.lastname: Wang
authors.forename: Georgios T
authors.initials: GT
authors.lastname: Noutsios
authors.forename: Anamika
authors.initials: A
authors.lastname: Singh
authors.forename: Susan L
authors.initials: SL
authors.lastname: Diangelo
authors.forename: Olabisi
authors.initials: O
authors.lastname: Sanusi
authors.forename: Manmeet
authors.initials: M
authors.lastname: Raval
authors.forename: Joanna
authors.initials: J
authors.lastname: Floros