Arylsulfatase D Gene in Xp22.3 Encodes Two Protein Isoforms

Abstract

The human genome contains six arylsulfatase genes (ARSA-ARSF), of which four are clustered in a distal region of the short arm of the X chromosome (Xp22.3). They were probably generated by a series of evolutionary duplication events; their exon-intron boundaries are identical. Nevertheless, different transcript lengths and the absence of cross-hybridizations point to a specific function of each gene in human cell metabolism, and multiple transcripts suggest the coding of protein isoforms. We identified a novel protein isoform of the ARSD gene by isolation of a series of cDNA clones from a human testis cDNA library. The clones were only partially identical to another series of ARSD clones isolated earlier (now designated ARSDalpha clones). Their specific C-terminal region (1160 nt) encodes a novel ARSD peptide of 48 amino acids and was identified as part of intron 6 of the ARSD gene in Xp22.3. We therefore designate them ARSDbeta clones. Expression analyses of ARSDalpha and ARSDbeta by semiquantitative RT-PCR revealed the presence of both in multiple human tissues, although in different quantities. A physiologic substrate for arylsulfatase D proteins is not known. We therefore estimated their sulfatase activities in vitro with the aid of the 4-methylumbelliferyl sulfate (4-MUS) assay. Surprisingly, neither ARSD protein isoform demonstrated any sulfatase activity alone or in combination, although their catalytic peptide domain is strongly conserved in comparison with that of the other X-chromosomal arylsulfatase enzymes (ARSC, ARSE, ARSF), all of which are functionally active in the 4-MUS assay.

Identification and biochemical characterization of an avian sulfatase homologous to the human ARSE, the gene for X-linked chondrodysplasia punctata

“…Their activity can be tested and distinguished using artificial substrates common to various arylsulfatases. Experiments performed in several laboratories show that the ARSD protein product does not show any activity against the artificial substrates (Franco et al, 1995;Urbitsch et al, 2000). ARSE and ARSF can be differentiated on the basis of biochemical features: ARSE is specifically inhibited by the coumarin derivative, warfarin, and it is heat labile whereas ARSF is not inhibited by this compound and is not sensitive to heating (Franco et al, 1995;Puca et al, 1997).…”

Steroid sulfatase inhibitors

“…In human cells, 12 different sulfatases have been well characterized (Table I). [1][2][3] Seven sulfatases are found in lysosomes, where they function under acidic conditions in degradative pathways of glycosaminoglycans and sulfolipids. Five sulfatases (arylsulfatases C-G) are not located in lysosomes, but are associated with intracellular membranes and feature a neutral pH optimum; whereas the natural substrates for arylsulfatases D-G are unknown, arylsulfatase C is involved in the desulfation of steroid 3-O-sulfates and hence is named STS (E.C.…”

“…94 It was shown that the side chain residues mimicking the CD-rings of EMATE have to be situated diagonally opposite to the sulfamate group (2,6-or 3,7-disubstitution pattern) for high potency; for example, compounds with a 2,7-disubstitution pattern were less active by at least two orders of magnitude. This can be explained by a better fit when overlaying the steroidal lead EMATE with the substituted chromenone sulfamate 2 -connected moieties (compare 34a and 34b with 34h and 34c, respectively), and fully branched, bulky groups are superior to linear chains (compare 34d and 34e with 34g and 34f, respectively). Most preferred are bicyclic (34i) and tricyclic aliphatic R groups such as the adamantyl residue (34j).…”

Single nucleotide polymorphism within arylsulfatase D gene (ARSD) is associated with selected kinematic parameters of sperm motility in Holstein-Friesian bulls

“…The literature on bovine ARSD is very poor. The enzyme was found in cauda epididymal fluid from mature Holstein bulls (Moura et al 2010) but its specific function is rather unknown since the substrate of human ARSD was not identified (Urbitsch et al 2000). Our results suggest that ARSD might be involved in new role -motility of sperms, although in unknown manner.…”