Biomedical subjects
Publications and source records attributed to L Bibi.
Mutation analysis performed on two Italian patients with alpha-mannosidosis allowed the identification of two new mutations, IVS20-2A>G and 322-323insA. The patients were both homozygous for these mutations. The first mutation causes skipping of exon 21, whereas the second causes a frameshift introducing a stop codon at position 160 of the amino acid sequence.
Beta-mannosidase is an exoglycosidase involved in the degradation of N-linked oligosaccharides moieties of glycoproteins. Lack of beta-mannosidase activity leads to the lysosomal disorder beta-mannosidosis (MIM 248510). We have isolated and sequenced the gene encoding the mouse beta-mannosidase. Comparison of the deduced amino acid sequence of mouse, human, bovine, and goat beta-mannosidase showed 64%, identity, reflecting a high degree of evolutionary conservation. Analysis of a multiple tissue northern blotting revealed a major transcript of about 3.7 kb in all tissues examined. The northern analysis also demonstrates that there is differential tissue mRNA expression. The mouse beta-mannosidase gene (Bmn) was mapped to the distal end of Chromosome (Chr) 3, in a region that is homologous with a segment of human Chr 4 containing the orthologous human gene.
Sulphamidase is an exoglycosidase involved in the degradation of heparan sulfate. Lack of sulphamidase activity leads to the lysosomal storage disorder Mucopolysaccharidosis type IIIA (Sanfilippo type A OMIM No. 252900). At present there are no naturally occurring small animal models of this disease that could be of fundamental importance to study the pathophysiology of the disease and to try therapeutic strategies. Cloning of the mouse gene is an important step to create a mouse model for this common mucopolysaccharidosis. We have isolated and sequenced the gene encoding mouse sulphamidase. Comparison of the deduced amino acid sequences of human and mouse sulphamidase showed 88% identity and 93% similarity. The exon-intron structure of the gene has been determined with the mouse 10-kb gene divided in 8 exons. The mouse sulphamidase gene (Sgsh) was mapped to the distal end of Chromosome (Chr) 11, in a region that is homologous with a segment of human Chr 17 containing the orthologous human gene.