Matrix morphogenesis in cornea is mediated by the modification of keratan sulfate by GlcNAc 6-O-sulfotransferase.
Matrix assembly and homeostasis in collagen-rich tissues are mediated by interactions with proteoglycans (PGs) substituted with sulfated glycosaminoglycans (GAGs). The major GAG in cornea is keratan sulfate (KS), which is N-linked to one of three PG core proteins. To ascertain the importance of the carbohydrate chain sulfation step in KS functionality, we generated a strain of mice with a targeted gene deletion in Chst5, which encodes an N-acetylglucosamine-6-O-sulfotransferase that is integral to the sulfation of KS chains. Corneas of homozygous mutants were significantly thinner than those of WT or heterozygous mice. They lacked high-sulfated KS, but contained the core protein of the major corneal KSPG, lumican. Histochemically stained KSPGs coassociated with fibrillar collagen in WT corneas, but were not identified in the Chst5-null tissue. Conversely, abnormally large chondroitin sulfate/dermatan sulfate PG complexes were abundant throughout the Chst5-deficient cornea, indicating an alteration of controlled PG production in the mutant cornea. The corneal stroma of the Chst5-null mouse exhibited widespread structural alterations in collagen fibrillar architecture, including decreased interfibrillar spacing and a more spatially disorganized collagen array. The enzymatic sulfation of KS GAG chains is thus identified as a key requirement for PG biosynthesis and collagen matrix organization.
Hayashida
Yasutaka
Y
Department of Ophthalmology, Osaka University Medical School, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
Akama
Tomoya O
TO
Beecher
Nicola
N
Lewis
Philip
P
Young
Robert D
RD
Meek
Keith M
KM
Kerr
Briedgeen
B
Hughes
Clare E
CE
Caterson
Bruce
B
Tanigami
Akira
A
Nakayama
Jun
J
Fukada
Michiko N
MN
Tano
Yasuo
Y
Nishida
Kohji
K
Quantock
Andrew J
AJ
D000818:Animals; D003315:Cornea / Q000737:chemistry / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D006579:Heterozygote; D006720:Homozygote; D007632:Keratan Sulfate / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout; D009024:Morphogenesis; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D014961:X-Ray Diffraction; D000097811:Carbohydrate Sulfotransferases
D007632:Keratan Sulfate; D015238:Sulfotransferases; D000097811:Carbohydrate Sulfotransferases