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Characterization of Inhibin/Activin Subunit: RESULTS(2)

Surprisingly, low levels of GDF9 and ZP3 mRNA, which were included as ‘‘oocyte-specific’’ markers, were observed in 40% and 80% (respectively) of the cumulus samples. antibiotics levaquin

Expression of activin receptor subtype and FS315 mRNA was examined during oocyte meiotic maturation. All mRNA species examined were detectable at all three nuclear maturational stages. However, the steady-state mRNA levels for ActRIIA, ActRIIB, and ActRIB appeared to vary during maturation. In particular, the ActRIIB PCR product signal intensity was lower (p < 0.05) in M1 oocytes compared to either GV or M2 oocytes, while for ActRIB, the PCR signal intensity was lower in M1 oocytes than in M2 oocytes (p < 0.05). For ActRIIA, the PCR product in GV oocytes appeared to be higher than that in either M1 or M2 oocytes (p = 0.05 and p < 0.05, respectively).

Like human oocytes, mouse oocytes did not express inhibin/activin subunits. However, in contrast to findings in human oocytes, FS315 transcripts were not detected in mouse oocytes (Table 2) despite their easy detection in mouse ovary RNA (data not shown). In contrast, 50-75% of hatching-stage blastocysts expressed the activin pA and pB subunits and FS315, but not a-subunit mRNA. All four activin receptor subtype mRNAs were present in both oocytes and embryos, and their detection frequencies were comparable between mouse oocytes, blastocysts, and human oocytes. As expected, high levels of GDF9 and ZP3 were found in all mouse oocyte samples, but neither was found in embryos.

TABLE 2. Percentage of the total number of cumulus, oocyte, or embryo samples expressing activin/inhibin system and control target mRNAs analyzed by RT-PCR.

Target Human Mouse
Oocyte” Cumulusb Oocytec : Embyod
FS315 95 100 0 75
Inh-a 11 100 0 0
Inh-pA 0 100 0 50
Inh-pB 0 80 0 50
ActRIIA 88 100 78 89
ActRIIB 100 100 100 100
ActRIA 95 100 87 100
ActRIB 93 90 87 75
GDF9 100 40 100 0
ZP3 100 80 100 0

a n = 38-43. b n = 10.
c n = 7-26; each contained 1-5 oocytes.
d n = 6-9 (for Inh-a n = 3); each contained 2-5 embryos at blastula stage.