6-O-sulfation enzyme which catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to position 6 of the N-sulfoglucosamine residue (GlcNS) of heparan sulfate. Required for muscle development and angiogenesis. 3'-phosphoadenylyl sulfate + alpha-D-glucosaminyl-[heparan sulfate](n) = 6-sulfo-alpha-D-glucosaminyl-[heparan sulfate](n) + adenosine 3',5'-bisphosphate + H(+) Expressed ubiquitously during gastrulation. During early somitogenesis, strong expression in head and presumptive brain. During mid-somitogenesis, strong expression in eye, hindbrain and somitic boundaries and weak expression in tail bud. During late somitogenesis, strong expression in eye, hindbrain, branchial arch primordia, spinal cord and ventral medial somites. At 24 hours post-fertilization (hpf), strong expression throughout the head, with expression receeding from the trunk spinal cord, ventral medial somites and somitic boundaries; expressed in cells surrounding vascular structures of the dorsal aorta and caudal vein in the tail. At 36 hpf, expressed in lens, optic stalk, hindbrain and pectoral fin. At 48 hpf, expressed in eye, brain, otic vesicle and branchial arches. Expressed both maternally and zygotically throughout the cleavage, gastrulation and somitogenesis stages. Morpholino knockdown results in defects in the branching morphogenesis of the caudal vein and defects in somite specification with impaired muscle differentiation. Belongs to the sulfotransferase 6 family.