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.
State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, 220 Handan Road, Shanghai 200433, People's Republic of China. yfan@fhcrc.org
Yuxin
Y
Fan
Long
L
Yu
Qiang
Q
Tu
Ruomu
R
Gong
Ying
Y
Jiang
Qi
Q
Zhang
Fangyan
F
Dai
Chiyuan
C
Chen
Shouyuan
S
Zhao
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