The Preliminary Study Of The Function Of AtZW10 Protein In Arabidopsis

The ZW10 protein is much conserved during the evolution of higher eukaryotes. In animal cells, a large number of studies show that ZW10 is required for proper chromosome segregation during both mitosis and meiosis. The protein is also found to be involved in membrane trafficking between the endoplasmic reticulum (ER) and Golgi apparatus. Multiple sequence alignment of ZW10 homologues shows that there are a number of identical regions in ZW10 sequences, suggesting that the proteins in different organisms may have similar functions. In this paper, AtZW10, a homologous protein of ZW10, was studied in Arabidopsis. Reverse transcription-PCR analysis andβ-glucuronidase staining show that AtZW10 is expressed in different organs. However, this expression is much stronger in flowers and seeds. The subcellular localization of AtZW10 was also examined, and it was found to be localized in the nucleus and cytoplasm. However, the distribution in the nucleus even more significant. To investigate AtZW10 function, T-DNA insertion mutants were analyzed. The phenotypes of zw10 mutants were undistinguishable from those of wild-type plants under normal growth conditions. Under different stresses, mutant seeds germinated obviously faster than the wild type. These data suggested that AtZW10 may be implicated in the process of seed germination as a negative regulator.Further research showed that AtZW10 affected cell division and early embryonic development. In mitotic mutant cells, lagging chromosomes were seen. The process took place at anaphase. Additionally, many defects were found in the meiotic mutant cells, which occurred at different stages of cell division. These anomalies include chromosome fragments, unequal or asynchronous segregation of chromosomes, and lagging chromosomes.Moreover,the loss-of-function mutations of AtZW10 caused the arrest of early embryo development. Most mutant embryos were found to be arrested at the two-cell stage. In addition, the cell division pattern of the mutant embryos is often changed. Longitudinal division planes of the proembryo are frequently replaced by transverse divisions and less frequently by unique divisions.Preliminary analysis shows Arabidopsis MAG2 (RINT-1 in animal cells) also seemed to interact with AtZW10 and to be involved in the membrane trafficking between the ER and the Golgi complex. In short, results showed that AtZW10,a rather conservative protein in evolution, has a variety of important biological functions.