Loss of O-GlcNAcase catalytic activity leads to defects in mouse embryogenesis

Villő Muha,Florence Authier,Zsombor Szoke-Kovacs,Sara Johnson,Jennifer Gallagher,Alison Mcneilly,Rory J Mccrimmon,Lydia Teboul,Daan M.F Van Aalten

doi:10.1016/j.jbc.2021.100439

Villő Muha, Florence Authier + Show 7 more

Open Access

https://doi.org/10.1016/j.jbc.2021.100439

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Abstract

O-GlcNAcylation is an essential post-translational modification that has been implicated in neurodevelopmental and neurodegenerative disorders. O-GlcNAcase (OGA), the sole enzyme catalyzing the removal of O-GlcNAc from proteins, has emerged as a potential drug target. OGA consists of an N-terminal OGA catalytic domain and a C-terminal pseudo histone acetyltransferase (HAT) domain with unknown function. To investigate phenotypes specific to loss of OGA catalytic activity and dissect the role of the HAT domain, we generated a constitutive knock-in mouse line, carrying a mutation of a catalytic aspartic acid to alanine. These mice showed perinatal lethality and abnormal embryonic growth with skewed Mendelian ratios after day E18.5. We observed tissue-specific changes in O-GlcNAc homeostasis regulation to compensate for loss of OGA activity. Using X-ray microcomputed tomography on late gestation embryos, we identified defects in the kidney, brain, liver, and stomach. Taken together, our data suggest that developmental defects during gestation may arise upon prolonged OGA inhibition specifically because of loss of OGA catalytic activity and independent of the function of the HAT domain.

Highlights

O-GlcNAcylation and the O-GlcNAc cycling enzymes are critical for normal development in several organisms
Previous studies have established that Oga is essential for mammalian development [19, 54]
Similar to the Oga KO (OgaKO) mouse models, the loss of OGA catalytic activity leads to reduced growth and perinatal lethality in our OGA catalytic-deficient model, suggesting that it is the loss of OGA enzymatic function that causes lethality and alteration in mouse embryonic development

Summary

Results

To dissect the role of OGA catalytic activity in mammalian development, we designed an Oga constitutive knock-in mouse model where OGA enzymatic activity is abolished (Fig. 1, A and B). The weight and volume of homozygous OgaD285A 18.5 dpc embryos (weight: 1023 ± 175 mg, n = 15; volume: 887 ± 86 mm, n = 8) were significantly reduced compared with WT (weight: 1197 ± 107.1 mg, n = 16; volume: 1020 ± 62 mm, n = 8) and heterozygous embryos (weight: 1176 ± 124 mg, n = 50; volume: 1038 ± 88 mm, n = 8) (Fig. 2, C and D). Taken together, these experiments show that catalytic deficiency of OGA leads to perinatal lethality and reduced growth.

E18.5 WEANING

Discussion

Experimental procedures