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Genetic differences in glucose phosphate isomerase activity among mouse embryos
1Department of Obstetrics and Gynaecology, University of Edinburgh, UK.
Development (Cambridge, England)
|November 1, 1989
Summary
Mouse embryo glucose phosphate isomerase (GPI-1) activity from the oocyte persists for 4.5 days, regardless of initial levels. Embryo-derived GPI-1 is detected at 3.5 days in all groups, showing gene activation is independent of maternal enzyme stores.
Area of Science:
- Developmental Biology
- Genetics
- Biochemistry
Background:
- Maternal factors play a crucial role in early embryonic development.
- Glucose phosphate isomerase (GPI-1) is an essential enzyme with maternal and embryonic contributions.
- Understanding the interplay between maternal and embryonic enzyme activity is key to deciphering developmental regulation.
Purpose of the Study:
- To investigate the persistence and influence of oocyte-coded glucose phosphate isomerase (GPI-1) activity in early mouse embryos.
- To determine if the activity level of maternal GPI-1 affects its survival time in the embryo.
- To ascertain if embryonic GPI-1 gene expression is detected earlier in embryos with lower maternal GPI-1 levels.
Main Methods:
- Comparison of mouse embryos from three congenic genotypes with varying levels of oocyte-coded GPI-1 activity.
- Enzyme activity assays to measure total GPI-1 and allozyme ratios in early embryos.
- Calculation of oocyte-coded and embryo-coded GPI-1 activity at different developmental stages.
Main Results:
- Oocyte-coded GPI-1 activity remained relatively constant for the first 2.5 days of development across all groups.
- Maternally derived GPI-1, particularly the less stable GPI-1C allozyme, disappeared by 5.5 days in low-activity groups.
- Embryonic Gpi-1 gene activation occurred at 3.5 days (compacted morulae) in all groups, irrespective of maternal GPI-1 levels or initial activity.
- The level of oocyte-coded GPI-1 at the onset of embryonic gene expression was higher in the high-activity group compared to the low-activity group.
Conclusions:
- The survival time of oocyte-coded GPI-1 activity in early mouse embryos is not significantly affected by its initial activity level in the oocyte.
- Embryonic Gpi-1 gene activation is an independent process that occurs at a consistent stage, regardless of the amount of maternally supplied GPI-1.
- While maternal GPI-1 stores can influence the enzyme environment, they do not dictate the timing of embryonic gene expression for Gpi-1.