m-Calpain is required for preimplantation embryonic development in mice.
m-Calpain is required for preimplantation embryonic development in mice.
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DOI：
10.1186/1471-213x-6-3
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发表时间：
2006-01-24
影响因子：
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通讯作者：
Greer PA
中科院分区：
文献类型：
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作者：
Dutt P;Croall DE;Arthur JS;Veyra TD;Williams K;Elce JS;Greer PA
μ-calpain和m-calpain是普遍表达的蛋白酶，与细胞迁移、细胞周期进程、退行性过程和细胞死亡有关。这些异二聚体酶由不同的催化亚基组成，由Capn1 （μ-calpain）或Capn2 （m-calpain）编码，以及由Capn4编码的共同调控亚基组成。小鼠Capn4基因的破坏破坏了μ-calpain和m-calpain的活性，并导致胚胎致死性，从而提示这两种酶中的一种或两种在哺乳动物胚胎发生过程中发挥重要作用。Capn1基因的破坏产生了可繁殖的小鼠，这意味着m-calpain可以弥补μ-calpain的缺失，或者m-calpain的缺失是导致Capn4-/-小鼠死亡的原因。为了区分上述选择，我们在胚胎干细胞中删除了小鼠Capn2基因的一个基本编码区，并通过小鼠种系传递了该突变等位基因。杂合动物的繁殖不能产生纯合突变的活后代或植入胚胎。建立了巢式PCR基因分型方案，在桑葚胚期检测到纯合子着床前突变胚胎，而在胚细胞期未检测到。我们得出结论，Capn2基因的纯合破坏导致了桑葚胚期和囊胚期的着床前胚胎死亡。这说明μ-calpain和m-calpain具有不同的功能，m-calpain对小鼠着床前胚胎的发育至关重要。
μ-calpain and m-calpain are ubiquitously expressed proteases implicated in cellular migration, cell cycle progression, degenerative processes and cell death. These heterodimeric enzymes are composed of distinct catalytic subunits, encoded by Capn1 (μ-calpain) or Capn2 (m-calpain), and a common regulatory subunit encoded by Capn4. Disruption of the mouse Capn4 gene abolished both μ-calpain and m-calpain activity, and resulted in embryonic lethality, thereby suggesting essential roles for one or both of these enzymes during mammalian embryogenesis. Disruption of the Capn1 gene produced viable, fertile mice implying that either m-calpain could compensate for the loss of μ-calpain, or that the loss of m-calpain was responsible for death of Capn4-/- mice. To distinguish between the alternatives described above, we deleted an essential coding region in the mouse Capn2 gene in embryonic stems cells and transmitted this mutant allele through the mouse germline. Breeding of heterozygous animals failed to produce homozygous mutant live offspring or implanted embryos. A nested PCR genotyping protocol was established, and homozygous preimplantation mutant embryos were detected at the morula but not at the blastocyts stage. We conclude that homozygous disruption of the Capn2 gene results in pre-implantation embryonic lethality between the morula and blastocyst stage. This establishes that μ-calpain and m-calpain have distinct functions, and that m-calpain is vital for development of the preimplantation murine embryo.