The centrosomal protein centrosomin A and the nuclear protein centrosomin B derive from one gene by post-transcriptional processes involving RNA editing.
The identification of a gene encoding concomitantly a nuclear protein and an intrinsic centrosomal protein further emphasizes the close and presumably developmental relationship between the cell nucleus and the centrosome. Screening of a murine RNA-based cDNA library with an antiserum to a centrosomal protein and rescreening with the insert of an initial clone released two complete cDNAs (1.2 kbp and 2.2 kpb) coding for proteins with notable characteristics. The amino-terminal sections of centrosomin A (276 amino acid residues, molecular mass 34.5 kDa) and of centrosomin B (447 amino acid residues, molecular mass 54.8 kDa) are identical over 272 amino acid residues. The carboxy-terminal section of the larger protein comprises additional 175 amino acid residues including nuclear location signals. The mRNAs encoding centrosomin A and B derive from a single gene. Chromogenomic DNA as template and primer pairs complementary to the sequence which is identical in centrosomin A and B cDNAs results in amplification of only one DNA fragment. Moreover, one exon of the genomic sequence and the centrosomin B-encoding cDNA sequence include a G which is deleted in the centrosomin A-encoding cDNA. Accordingly, the two mRNAs are the products of either alternative splicing or alternative polyadenylation in combination with RNA editing. The recombinantly expressed chimeric protein consisting of centrosomin A and the green fluorescent protein from Aequorea victoria accumulates in centrosomes while the corresponding fusion protein with the centrosomin B sequence is transported into nuclei.
Petzelt
C
C
Clinic for Anaesthesiology and Intensive Care, Charité, Humboldt-University, Berlin, Germany. petzelt@ukrv.de
Joswig
G
G
Mincheva
A
A
Lichter
P
P
Stammer
H
H
Werner
D
D
D000595:Amino Acid Sequence; D000818:Animals; D000941:Antigens / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D034961:Antigens, Nuclear; D001483:Base Sequence; D018385:Centrosome; D018076:DNA, Complementary; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D017433:Protein Structure, Secondary; D017393:RNA Editing; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D000941:Antigens; D034961:Antigens, Nuclear; D018076:DNA, Complementary; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C069516:centrosomin A