林蛙卵收缩因子的进一步纯化(简报)

FURTHER PURIFICATION OF CONTRACTION FACTOR(S) FROM BLASTULAE OF RANA AMURENSIS

大家承认动物细胞的胞质分裂是由收缩环的微丝束收缩而引起的。那么微丝束又是在什么物质作用下诱发产生的呢?两栖类卵的第一次胞质分裂是单侧卵裂(unilateral cleavage),即先在动物极出现分裂沟。

During the cleavage of frog egg the cleavage furrow contracts. It has been shown that contraction factor(s) existed in blastula and mature eggs of Rana amurensis, which could induce the contraction of fertilized egg surface after being injected^(3). This factor(s) was prepared as partially purified fraction from the homogenatc of blastula by centrifugation at 120,000gfor 1.5 hr and by fractionation through the Scphacryl S-300 and DEAE-Sepharose column. 5—6 deeply stained protein bands could be distinguished after SDS-polyacrylamide electrophoresis.This short communication reports the purification of the above active fraction by immunoaffinity chromatography. Guinea pigs were immunized with above active fraction, the immunoglobulin containing fraction was isolated by ammonium sulfate and linked to Sepharose 4 B. Protein absorbed on the column was eluted with Glycine-HCI buffer, pH 2.7, after the supernatant of the blastula homogenate had passed through the column. The eluate was active in bioassy as 8 out of 10 eggs were contracted after being injected. The column was still effective after regeneration. SDS-polyacrylamide elcctrophoresis shows that the supernatant of the blastula homegenate contains more than 30 protein bands (Fig. 1 A) and the supcrnatant passing the affinity column (Fig. 1 B) has similar protein component as shown in Fig. 1 A. Fig. 1 C is the purified active fraction containing 4 major protein bands. By comparing with the protein markers of known molecular weight (Fig. 1 D), it is evident that a protein band corresponding to actin is eliminated from partially purified fraction used for immunization. These results suggests that (1) the active contraction factor(s) is immunogenic and (2) the action of contraction factor(s) is probably resulted not from the increase of large amount of actin injected but from factor(s) that could induce the formation of microfilament from actin already present in the fertilized eggs.