Molecular cloning, genomic organization, and mapping of beta 4GalT-VIb, a brain abundant member of beta 4-galactosyltransferase gene family, to human chromosome 18q12.1.
In the present study, a brain abundant member of beta 4-galactosyltransferase gene family with an open reading frame encoding 343 amino acids was cloned and identified from a human leukemia cell cDNA library. The putative protein sequence is about 94.8 and 94.2% identical to the 382-amino-acid mouse and rat beta 4-galactosyltransferase respectively and also contains cysteine residues previously shown to be important for the function of the gene family members. This cDNA (tentatively termed beta 4GalT-VIb) is identical to a recently reported cDNA (tentatively termed beta 4GalT-VIa) of human beta 4-galactosyltransferase except lacking one exon, suggesting that these two cDNAs are two different alternative transcripts of the same gene. Northern hybridization showed that the new alternative transcript, beta 4GalT-VIb, is expressed in all 16 human tissues tested with highest level in brain and rich level in testis, thymus and pancreas, whereas weak expression was detected in lung. The beta 4GalT-VIb gene was located to human chromosome 18q12.1 between markers WI-9180 and SGC35630 by radiation hybrid mapping. The genomic organization and adjacent gene content of beta 4GalT-VIb were identified by comparing its cDNA sequence with three genomic sequences AC017100, AP002474 and AP001336, which showed that beta 4GalT-VIb spans an approximately 58 kb region and is composed of 8 exons. In addition, the most conserved motif composed of 41 residues, LXYX3FGGVSXL(T/S)X2 QFX2INGFPNX(Y/F)WGWGGEDDDX2NR, was defined according to 17 sequences of beta 4GalTs from seven different organisms for the first time.
Fan
Yuxin
Y
State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China. yfan@fhcrc.org
Yu
Long
L
Tu
Qiang
Q
Gong
Ruomu
R
Jiang
Ying
Y
Zhang
Qi
Q
Dai
Fangyan
F
Chen
Chiyuan
C
Zhao
Shouyuan
S
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D001921:Brain; D002417:Cattle; D002874:Chromosome Mapping; D002887:Chromosomes, Human, Pair 18; D020224:Expressed Sequence Tags; D005700:Galactosyltransferases / Q000235:genetics*; D015894:Genome, Human; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D051381:Rats; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D005700:Galactosyltransferases; C427754:beta4-galactosyltransferase VI