Mouse cellular nucleic acid binding proteins: a highly conserved family identified by genetic mapping and sequencing.

Human cellular nucleic acid binding protein (CNBP) is a zinc finger DNA binding protein of unknown function. The human CNBP cDNA was used as a probe to isolate four structurally distinct but highly homologous mouse liver cDNA clones. Each of the mouse clones exhibited extraordinary sequence conservation with human CNBP cDNA, and the predicted mouse amino acid sequence identities with human CNBP protein ranged from 99 to 100%. Genetic mapping of CNBP genes in interspecific and intersubspecific mouse backcrosses revealed two loci that hybridize to CNBP cDNA at high stringency, located on chromosomes 5 and 6. The subcellular distribution of the CNBP protein was characterized with a specific polyclonal antibody generated against a synthetic peptide from the carboxyl terminus. CNBP was found in the cytosol and the endoplasmic reticulum in subcellular fractions from mouse liver, but was undetectable in nuclear fractions. These data suggest that CNBP is a member of a highly conserved family of cytosolic proteins that may be encoded by multiple dispersed genes

Identification of a mutation cluster in mevalonate kinase deficiency, including a new mutation in a patient of Mennonite ancestry.

Mevalonate kinase (MKase) deficiency (MKD) is a rare autosomal recessive disorder in the pathway of cholesterol and nonsterol isoprenoid biosynthesis. Thus far, two disease-causing missense alleles have been identified, N301T and A334T. We report four additional mutations associated with MKD: L264F, T243I, L265P, and I268T, the last found in a patient of Mennonite ancestry. Electrophoretic analysis of bacterially expressed wild-type and mutant MKase indicated that I268T and T243I mutants produced normal or somewhat reduced amounts of MKase protein; conversely, L264F and L265P mutations resulted in considerably decreased, or absent, MKase protein. Immunoblot analysis of MKase from all patients suggested that the MKase polypeptide was grossly intact and produced in amounts comparable to control levels. Three mutations resulted in significantly diminished MKase enzyme activity (<2%), whereas the I268T allele yielded approximately 20% residual enzyme activity. Our results should allow more-accurate identification of carriers and indicate a mutation "cluster" within amino acids 240-270 of the mature MKase polypeptide