Existence of a bovine LINE repetitive insert that appears in the cDNA of bovine protein BCNT in ruminant, but not in human, genomes.
A novel protein, BCNT, originally isolated from bovine brain and named after Bucentaur, contains an internal portion that is translated from part of bovine LINE repetitive sequence (Bov-B LINE). Human cDNA highly homologous to the bovine bcnt (bbcnt) cDNA has been isolated but does not contain a sequence similar to the Bov-B LINE insert (Nobukuni, T., Kobayashi, M., Omori, A., Ichinose, S., Iwanaga, T., Takahashi, I., Hashimoto, K., Hattori, S., Kaibuchi, K., Miyata, Y., Masui, T., Iwashita, S., 1997. An Alu-linked repetitive sequence corresponding to 280 amino acids is expressed in a novel bovine protein, but not in its human homologue. J. Biol. Chem. 272, 2801-2807). In this study, we conducted a polymerase chain reaction analysis to investigate whether such a Bov-B LINE insert is present in bcnt orthologs in other animals and in the genomic sequence of the human BCNT (hBCNT) gene. The results indicate that the Bov-B LINE insert is present in the genomic sequences of bcnt orthologs from sheep, goats, axis deer, and mouse deer (chevrotain), that is in Ruminantia, but not in pigs or human. Analysis of the bbcnt genomic sequence around the Bov-B LINE insert revealed a large part of the inserted Bov-B LINE sequence to be included in an exon; this is followed by a 54-nucleotide sequence that is highly homologous to Bov-B LINE in the 3'-side intron. The hBCNT gene was isolated and found to consist of seven exons and six introns, among which the intron corresponding to the Bov-B LINE insertion site in the bbcnt genome is 16.5kb in length with no sequence similar to Bov-B LINE. Based on these results, it seems likely that the Bov-B LINE insert is derived from a long Bov-B LINE repetitive sequence transposed to an ancestral bcnt gene in Ruminantia and reformed as a new exon through new splicing sites in the transposed sequence.
Takahashi
I
I
National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
Nobukuni
T
T
Ohmori
H
H
Kobayashi
M
M
Tanaka
S
S
Ohshima
K
K
Okada
N
N
Masui
T
T
Hashimoto
K
K
Iwashita
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002874:Chromosome Mapping; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D004251:DNA Transposable Elements / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics*; D015870:Gene Expression / Q000235:genetics; D005796:Genes / Q000235:genetics; D015894:Genome, Human; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010750:Phosphoproteins; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics*; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D018626:Retroelements; D012418:Ruminants / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
C104422:CFDP1 protein, human; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; D018626:Retroelements