title: RAPADILINO RECQL4 mutant protein lacks helicase and ATPase activity.
abstract: The RecQ family of helicases has been shown to play an important role in maintaining genomic stability. In humans, this family has five members and mutations in three of these helicases, BLM, WRN and RECQL4, are associated with disease. Alterations in RECQL4 are associated with three diseases, Rothmund-Thomson syndrome, Baller-Gerold syndrome, and RAPADILINO syndrome. One of the more common mutations found in RECQL4 is the RAPADILINO mutation, c.1390+2delT which is a splice-site mutation leading to an in-frame skipping of exon 7 resulting in 44 amino acids being deleted from the protein (p.Ala420-Ala463del). In order to characterize the RAPADILINO RECQL4 mutant protein, it was expressed in bacteria and purified using an established protocol. Strand annealing, helicase, and ATPase assays were conducted to characterize the protein's activities relative to WT RECQL4. Here we show that strand annealing activity in the absence of ATP is unchanged from that of WT RECQL4. However, the RAPADILINO protein variant lacks helicase and ssDNA-stimulated ATPase activity. These observations help explain the underlying molecular etiology of the disease and our findings provide insight into the genotype and phenotype association among RECQL4 syndromes.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, Baltimore, MD 21224, USA.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Croteau
authors.forename: Marie L
authors.initials: ML
authors.lastname: Rossi
authors.forename: Jennifer
authors.initials: J
authors.lastname: Ross
authors.forename: Lale
authors.initials: L
authors.lastname: Dawut
authors.forename: Christopher
authors.initials: C
authors.lastname: Dunn
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kulikowicz
authors.forename: Vilhelm A
authors.initials: VA
authors.lastname: Bohr
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001003:Anal Canal / Q000002:abnormalities / Q000378:metabolism; D003398:Craniosynostoses / Q000235:genetics; D004392:Dwarfism / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D005091:Exons; D056726:Genetic Association Studies; D042822:Genomic Instability; D006344:Heart Septal Defects, Atrial / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017880:Limb Deformities, Congenital / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010329:Patella / Q000002:abnormalities / Q000378:metabolism; D022821:RNA Splice Sites / Q000235:genetics*; D011884:Radius / Q000002:abnormalities / Q000378:metabolism; D053484:RecQ Helicases / Q000235:genetics* / Q000378:metabolism; D011038:Rothmund-Thomson Syndrome / Q000209:etiology / Q000235:genetics / Q000378:metabolism
chemical_list: D022821:RNA Splice Sites; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C506731:RECQL4 protein, human; D053484:RecQ Helicases