Zhang B, Chen Y, Han Z, Ris H, Zhai Z
College of Life Sciences, Peking University, Beijing, PR China.
FEBS Lett. 1998 May 22;428(1-2):52-6. doi: 10.1016/s0014-5793(98)00484-0.
We report here a new structure, named 'strings-of-pearls', which are seen to form in Xenopus egg extracts after incubation, as 200 nm membrane vesicles attach to 10 nm filaments. These membrane vesicles fuse together along the filaments to form annulate lamellae (AL) or attach to demembranated sperm chromatin to initiate assembly of a nuclear envelope. Immunoassay with anti-keratin antibodies AE3 showed that the filaments were mainly composed of a 56 kDa keratin-like protein. Addition of AE3 to the extracts resulted in inhibition of AL formation and defective assembly of NE. These results suggest a function of keratins in the assembly of nuclear envelopes during Xenopus development.
