Disruption of CCTbeta2 expression leads to gonadal dysfunction.

Area of Science:

• Biochemistry
• Molecular Biology
• Reproductive Biology

Background:

• Mammalian CTP:phosphocholine cytidylyltransferase (CCT) enzymes are crucial for membrane phospholipid biogenesis.
• CCT isoforms, including CCTalpha, CCTbeta2, and CCTbeta3, exhibit distinct tissue expression patterns.
• CCTbeta2 is notably expressed in the brain, lungs, and gonads, though at low levels compared to CCTalpha.

Purpose of the Study:

• To investigate the physiological roles of the CCTbeta2 isoform by generating and analyzing CCTbeta2 knockout mice.
• To determine the impact of CCTbeta2 deficiency on reproductive functions in both female and male mice.

Main Methods:

• Generation of CCTbeta2 knockout (CCTbeta2(-/-)) mouse models.
• Quantitative analysis of CCT transcript levels in various tissues.
• Histopathological examination of gonads (ovaries and testes) in knockout and wild-type mice.
• Hormonal level assessments (FSH, LH) in knockout mice.
• Fertility assessments in male CCTbeta2 knockout mice.

Main Results:

• CCTbeta2 knockout mice showed no overt defects in brain or lung tissues.
• Female CCTbeta2(-/-) mice exhibited sterility, defective ovarian follicle development, and increased incidence of ovarian tumors with age.
• Male CCTbeta2(-/0) mice displayed progressive testicular degeneration and reduced fertility, despite normal hormone levels.
• Defective ovaries in knockout females were associated with elevated FSH and LH levels, indicating a breakdown in gonadal response.

Conclusions:

• CCTbeta2 plays a critical, albeit previously unrecognized, role in maintaining gonadal function and reproductive capacity.
• Loss of CCTbeta2 leads to gonad degeneration and reproductive deficiency, particularly affecting ovarian response to hormonal stimulation.
• These findings underscore the importance of specific CCT isoforms in reproductive health, even when expressed at low levels.