The RNAtranscript of the GLB1 gene is alternatively spliced and produces 2 mRNAs. The 2.5-kilobase transcript encodes the beta-galactosidase enzyme of 677 amino acids. The alternative 2.0-kb mRNA encodes a beta-galactosidase-related protein (S-Gal) that is only 546 amino acids long and that has no enzymatic activity. The S-Gal protein does bind elastin and fragments of elastin that are generated by proteolysis.[6]
The S-Gal protein functions during the normal assembly of elastin into extracellularelastic fibers. Elastin is initially present as newly synthesized tropoelastin which can be found in association with S-Gal. The enzymatic activity of neuraminidase in the elastin receptor complex is involved in the release of tropoelastin molecules from the S-Gal chaperone.[10]Cathepsin A is also required for normal elastin biosynthesis.[11]
References
↑Shows TB, Scrafford-Wolff L, Brown JA, Meisler M (1978). "Assignment of a beta-galactosidase gene (beta GALA) to chromosome 3 in man". Cytogenetics and Cell Genetics. 22 (1–6): 219–22. doi:10.1159/000130940. PMID110522.
↑Oshima A, Tsuji A, Nagao Y, Sakuraba H, Suzuki Y (Nov 1988). "Cloning, sequencing, and expression of cDNA for human beta-galactosidase". Biochemical and Biophysical Research Communications. 157 (1): 238–44. doi:10.1016/S0006-291X(88)80038-X. PMID3143362.
↑Caciotti A, Donati MA, Boneh A, d'Azzo A, Federico A, Parini R, Antuzzi D, Bardelli T, Nosi D, Kimonis V, Zammarchi E, Morrone A (Mar 2005). "Role of beta-galactosidase and elastin binding protein in lysosomal and nonlysosomal complexes of patients with GM1-gangliosidosis". Human Mutation. 25 (3): 285–92. doi:10.1002/humu.20147. PMID15714521.
Kaye EM, Shalish C, Livermore J, Taylor HA, Stevenson RE, Breakefield XO (Jun 1997). "beta-Galactosidase gene mutations in patients with slowly progressive GM1 gangliosidosis". Journal of Child Neurology. 12 (4): 242–7. doi:10.1177/088307389701200404. PMID9203065.
Callahan JW (Oct 1999). "Molecular basis of GM1 gangliosidosis and Morquio disease, type B. Structure-function studies of lysosomal beta-galactosidase and the non-lysosomal beta-galactosidase-like protein". Biochimica et Biophysica Acta. 1455 (2–3): 85–103. doi:10.1016/S0925-4439(99)00075-7. PMID10571006.
Shows TB, Scrafford-Wolff L, Brown JA, Meisler M (1979). "Assignment of a beta-galactosidase gene (beta GALA) to chromosome 3 in man". Cytogenetics and Cell Genetics. 22 (1–6): 219–22. doi:10.1159/000130940. PMID110522.
Shows TB, Scrafford-Wolff LR, Brown JA, Meisler MH (Mar 1979). "GM1-gangliosidosis: chromosome 3 assignment of the beta-galactosidase-A gene (beta GALA)". Somatic Cell Genetics. 5 (2): 147–58. doi:10.1007/BF01539157. PMID113895.
Yoshida K, Oshima A, Sakuraba H, Nakano T, Yanagisawa N, Inui K, Okada S, Uyama E, Namba R, Kondo K (Mar 1992). "GM1 gangliosidosis in adults: clinical and molecular analysis of 16 Japanese patients". Annals of Neurology. 31 (3): 328–32. doi:10.1002/ana.410310316. PMID1353343.
Mosna G, Fattore S, Tubiello G, Brocca S, Trubia M, Gianazza E, Gatti R, Danesino C, Minelli A, Piantanida M (Nov 1992). "A homozygous missense arginine to histidine substitution at position 482 of the beta-galactosidase in an Italian infantile GM1-gangliosidosis patient". Human Genetics. 90 (3): 247–50. doi:10.1007/bf00220071. PMID1487238.
Oshima A, Yoshida K, Ishizaki A, Shimmoto M, Fukuhara Y, Sakuraba H, Suzuki Y (May 1992). "GM1-gangliosidosis: tandem duplication within exon 3 of beta-galactosidase gene in an infantile patient". Clinical Genetics. 41 (5): 235–8. doi:10.1111/j.1399-0004.1992.tb03672.x. PMID1606711.
Morreau H, Bonten E, Zhou XY, D'Azzo A (Sep 1991). "Organization of the gene encoding human lysosomal beta-galactosidase". DNA and Cell Biology. 10 (7): 495–504. doi:10.1089/dna.1991.10.495. PMID1909871.
Yamamoto Y, Hake CA, Martin BM, Kretz KA, Ahern-Rindell AJ, Naylor SL, Mudd M, O'Brien JS (Mar 1990). "Isolation, characterization, and mapping of a human acid beta-galactosidase cDNA". DNA and Cell Biology. 9 (2): 119–27. doi:10.1089/dna.1990.9.119. PMID2111707.
Morreau H, Galjart NJ, Gillemans N, Willemsen R, van der Horst GT, d'Azzo A (Dec 1989). "Alternative splicing of beta-galactosidase mRNA generates the classic lysosomal enzyme and a beta-galactosidase-related protein". The Journal of Biological Chemistry. 264 (34): 20655–63. PMID2511208.
Hoogeveen AT, Reuser AJ, Kroos M, Galjaard H (May 1986). "GM1-gangliosidosis. Defective recognition site on beta-galactosidase precursor". The Journal of Biological Chemistry. 261 (13): 5702–4. PMID3084469.
Verheijen FW, Palmeri S, Galjaard H (Jan 1987). "Purification and partial characterization of lysosomal neuraminidase from human placenta". European Journal of Biochemistry / FEBS. 162 (1): 63–7. doi:10.1111/j.1432-1033.1987.tb10542.x. PMID3102233.
Oshima A, Tsuji A, Nagao Y, Sakuraba H, Suzuki Y (Nov 1988). "Cloning, sequencing, and expression of cDNA for human beta-galactosidase". Biochemical and Biophysical Research Communications. 157 (1): 238–44. doi:10.1016/S0006-291X(88)80038-X. PMID3143362.
Sips HJ, de Wit-Verbeek HA, de Wit J, Westerveld A, Galjaard H (1985). "The chromosomal localization of human beta-galactosidase revisited: a locus for beta-galactosidase on human chromosome 3 and for its protective protein on human chromosome 22". Human Genetics. 69 (4): 340–4. doi:10.1007/BF00291653. PMID3921454.
Verheijen FW, Palmeri S, Hoogeveen AT, Galjaard H (Jun 1985). "Human placental neuraminidase. Activation, stabilization and association with beta-galactosidase and its protective protein". European Journal of Biochemistry / FEBS. 149 (2): 315–21. doi:10.1111/j.1432-1033.1985.tb08928.x. PMID3922758.
Goldman JE, Katz D, Rapin I, Purpura DP, Suzuki K (May 1981). "Chronic GM1 gangliosidosis presenting as dystonia: I. Clinical and pathological features". Annals of Neurology. 9 (5): 465–75. doi:10.1002/ana.410090509. PMID6791574.