Abstract
Disruption of the Heparan sulfate (HS)-biosynthetic gene N-acetylglucosamine N-Deacetylase/N-sulfotransferase 1 (Ndst1) during nervous system development causes malformations that are composites of those caused by mutations of multiple HS binding growth factors and morphogens. However, the role of Ndst function in adult brain physiology is less explored. Therefore, we generated mice bearing a Purkinje-cell-specific deletion in Ndst1 gene function by using Cre/loxP technology under the control of the Purkinje cell protein 2 (Pcp2/L7) promotor, which results in HS undersulfation. We observed that mutant mice did not show overt changes in the density or organization of Purkinje cells in the adult cerebellum, and behavioral tests also demonstrated normal cerebellar function. This suggested that postnatal Purkinje cell development and homeostasis are independent of Ndst1 function, or that impaired HS sulfation upon deletion of Ndst1 function may be compensated for by other Purkinje cell-expressed Ndst isoforms. To test the latter possibility, we additionally deleted the second Purkinje-cell expressed Ndst family member, Ndst2. This selectively abolished reproductive capacity of compound mutant female, but not male, mice, suggesting that ovulation, gestation, or female reproductive behavior specifically depends on Ndst-dependent HS sulfation in cells types that express Cre under Pcp2/L7 promotor control.
Highlights
Heparan sulfate (HS) is produced by most mammalian cells as part of membrane and extracellular matrix proteoglycans [1]
To study the roles of HS in adult brain homeostasis in vivo, mice harboring a conditional, loxP-flanked allele of N-Deacetylase/N-sulfotransferase 1 (Ndst1) (Ndst1f/f ) were crossed with transgenic mice expressing the bacteriophage recombinase Cre under the control of the Purkinje cell protein 2 (Pcp-2 or L7) promotor, which is predominantly expressed in postnatal cerebellar
Patched and Smoothened are expressed in cerebellar Purkinje cells [26,27], and Shh is known to play crucial roles in prenatal [52] and postnatal [53,54,55,56] development of the cerebellum
Summary
Heparan sulfate (HS) is produced by most mammalian cells as part of membrane and extracellular matrix proteoglycans [1]. The chain grows by exostosin (Ext) copolymerization of GlcAβ1,4 and GlcNAcα and is modified by one or more of the four Ndst isozymes; the N-deacetylase activity of Ndsts removes acetyl groups from GlcNAc residues, which are converted to GlcNS through the N-sulfotransferase activity. Subsequent modifications of the HS chain by most O-sulfotransferases and a GlcA C5-epimerase depend on the presence of GlcNS residues, making the Ndsts responsible for the generation of sulfated ligand binding sites in HS [2]. Ndst and Ndst mRNA are expressed in all embryonic and adult tissues examined, whereas Ndst and Ndst transcripts are predominantly expressed during embryonic development [3].
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