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Natalia Vega

Synchronization of circadian clock gene expression in cultured granulosa cells from hen preovulatory follicles
 
PURPOSE:
Understand how granulosa cells function in a circadian manner.

ISSUE:
How does the normal circadian rhythm in granulosa cells work, and what would happen in the absence of clock and clock-related genes?

BACKGROUND:

Granulosa cells:

  • Are differentiated and non-proliferative in preovulatory follicles.
  • Differentiation is determined by:
    • Ability to generate cyclic adenosine monophosphate in response to gonadotropins;
    • Progesterone production

Clock and clock-related genes:
Have a timing effect in a biological cycle.

  • Bmal1 – Promotes Per2 transcription in granulosa cells.
  • Per2 – Prevents its own production by Bmal1 when it becomes accumulated.
  • Id2 – Promotes differentiation in granulosa cells, and competes with Bmal1 for promoter region of Per2.

HYPOTHESES:

  • Do granulosa cells from preovulatory hen follicles exhibit in vivo circadian rhythms of clock and clock-related genes, including Per2, Bmal1, Dec1 and Id2?
  • Are these genes able to control the time in which ovulation occurs?

OBJECTIVES:

  • Establish a role for granulosa cell circadian rhythms in the timing of ovulation
  • Determine if Id2 is a clock gene regulator.

RESULTS:

  • Per2, Dec1 and Bmal1 gene expression in preovulatory follicle granulosa cells
  •  Granulosa cells have a rhythmic expression of Per2 and Bmal1 when synchronized by serum shock. 
  • Per2 and Bmal1 are able to induce a circadian rhythm in granulosa cells.
  • Per2 and Bmal1 may have a timing effect on ovulation and oviposition.

SIGNIFICANCE:

  • Reproductive enhancement of threatened and domesticated avian species.
  • Better understanding and improvement of women’s reproductive health.

CURRENT AND FUTURE STUDIES:
Determine the effect of LH, TGF-β, BMP6 and Id proteins on the synchronization of clock gene expression in granulosa cells.

 Currently: Will be studying Veterinary and Equine Technology at Murray State (Murray, Kentucky), Fall 2013

 

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