Expression of Prolyl 3-hydroxylase Genes in Embryonic and Adult Mouse Tissues

Abstract

ABSTRACT. Collagen requires hydroxylation of its proline residues to achieve proper assembly, structure, and function. Prolyl 4-hydroxylase catalyzes formation of 4-hydroxyproline, which is essential for collagen triple helix formation and stability. Prolyl 3-hydroxylase catalyzes formation of 3-hydroxyproline, which is far less abundant in collagens and whose function remains unclear. Recently mutations in prolyl 3-hydroxylase 1 have been associated with osteogenesis imperfecta, yet the temporal and spatial expression patterns of the prolyl 3-hydroxylase family members during development and in adult tissues remain undefined. By northern blot analysis distinct differences in transcript sizes of the three prolyl 3-hydroxylase genes were detected. Quantitative RTPCR demonstrated tissue-specific differences in prolyl 3-hydroxylase expression, most notable of which were high levels of prolyl 3-hydroxylase 2 in kidney and prolyl 3-hydroxylase 1 expression in embryonic tissues. Finally, in situ hybridization was used to assess spatio-temporal distribution of three prolyl 3-hydroxylases at embryonic days 11-15. Importantly, prolyl 3-hydroxylase 1 was expressed within cartilage condensations of the vertebral bodies and in the aortic arch of the developing heart, whereas prolyl 3-hydroxylase 2 was expressed in developing lens capsule. The prolyl 3-hydroxylase 3 gene showed more generalized expression overlapping somewhat with the other two genes. This report characterizes expression of the three prolyl 3-hydroxylase genes in embryonic and adult mice. Overall these data demonstrate tissue specific prolyl 3-hydroxylase gene expression in both fetal and adult tissues indicating a developmental role for prolyl 3-hydroxylase activity.

Posttranslational Modifications in Type I Collagen from Different Tissues Extracted from Wild Type and Prolyl 3-Hydroxylase 1 Null Mice

“…The most highly expressed enzyme type was P3H2. This finding is consistent with the previously published data for bone and skin (28). P3H1 was up-regulated in bone as compared with skin and tendon.…”

Post-translationally Abnormal Collagens of Prolyl 3-Hydroxylase-2 Null Mice Offer a Pathobiological Mechanism for the High Myopia Linked to Human LEPREL1 Mutations

“…1D). The expression pattern of P3h2 generated from this approach correlated with multiple previously reported expression analysis studies (15,32,33).…”

Recessive Mutations inLEPREL1Underlie a Recognizable Lens Subluxation Phenotype

“…6 Prolyl hydroxylation occurs as a post-translational modification for fibril-forming collagens such as collagens I, II, IV and V. 7 Murine models show that P3H2 is expressed in coordination with and interacts with basement membrane collagens such as type IV collagen. 8 Collagen type IV is found in the ciliary zonules, the lens capsule, and the inner limiting membrane of the retina; P3H2 inactivation as a result of defective collagen hydroxylation is likely to be the cause of zonular instability, cataract, and a predisposition to retinal tears/detachment in patients with recessive LEPREL1 mutations. 9,10 In addition, as disruption of the inner limiting membrane of the retina in chick embryos results in marked eye enlargement, a defective inner limiting membrane of the retina from recessive LEPREL1 mutations might lead to pediatric high myopia.…”