A homologue of the human regulator of mitotic spindle assembly protein (RMSA-1) is present in crane fly and is associated with meiotic chromosomes.
In a previous study, we have shown that a newly identified chromosomal protein, RMSA-1 (Regulator of Mitotic Spindle Assembly-1), identified and cloned using a human autoimmune, serum, is essential for mitotic spindle assembly; we proposed that RMSA-1 was a previously unknown physiological substrate for cdc 2 kinase. In the present study, we show that this protein is present in crane fly and is associated with the chromosomes of spermatocytes. A 31 kDa molecule in extracts from crane-fly nuclei, isolated from larvae, pupae and adults, reacts with affinity-purified anti-RMSA-1 autoantibody, shown by immunoblotting. The autoantibody reacts, as shown by immunofluorescence, with crane-fly spermatocyte chromosomes in prophase through anaphase of both meiosis-1 and meiosis-II but does not react with preprophase or telophase nuclei or with spermatid nuclei. In all meiotic stages, the crane-fly sex chromosomes stain more intensely than the autosomes. We conclude that, since RMSA-1 is present in insect and mammalian cells, it is conserved across a variety of animal species. Further, since RMSA-1 binds to chromosomes in meiotic cells, it also may be essential for assembly of the meiotic spindle.
Yeo
J P
JP
Department of Pathology, Monash University Medical School, Prahran, Victoria, Australia.
Forer
A
A
Toh
B H
BH
D000818:Animals; D000906:Antibodies; D016203:CDC2 Protein Kinase / Q000378:metabolism; D018797:Cell Cycle Proteins; D002875:Chromosomes / Q000502:physiology*; D003001:Cloning, Molecular; D004175:Diptera / Q000254:growth & development / Q000502:physiology*; D006801:Humans; D007814:Larva; D008297:Male; D008540:Meiosis / Q000502:physiology*; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D011679:Pupa; D013090:Spermatocytes / Q000166:cytology / Q000502:physiology*; D008941:Spindle Apparatus / Q000502:physiology*; D013379:Substrate Specificity
D000906:Antibodies; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C086078:RMSA-1 protein, human; D016203:CDC2 Protein Kinase