Analysis of Transcriptional Regulatory Region of Human I β-1,6-N-acetylglucosaminyltransferase Gene

人類I基因有三種isoforms，分別命名為IGnTA、IGnTB和IGnTC。這三種isoforms有相同的exon 2與exon 3，但卻有不同的exon 1 (1A、1B和1C)。它們的表現量在不同的組織或細胞中不盡相同，例如IGnTC僅表現在紅血球細胞，而IGnTB僅表現在水晶體上皮細胞，且每一個不同exon 1上游由不同的promoters所主導。在這次研究中，我們發現I基因A型(IGnTA)上游有兩段可能的調控區，一段在-75/+151區域，另一段在-2148/-1917區域。在+75/-151區域中有一段可能的GATA-1結合序列TGATAG，而在-2148/-1917區域中則有一段可能的NF-E2 / AP-1結合序列CTGAGTCA，而且在-2148/-1917區域中調控轉錄的序列很可能是一enhancer。

Human IGnT gene (I gene) have three isoforms designated IGnTA, IGnTB, and IGnTC , which contain different exon 1(1A,1B,and 1C) but share the common exon 2 and exon 3. The expression patterns of the three isoforms are tissue- or cell-specific. For example, IGnTC is the only one expressed in reticulocytes, whereas only the IGnTB is expressed in lens-epithelium cells. It is believed that the different exon 1 of I gene are preceded with distinct promoters. In this study, we found that there are two positive regulatory elements, one in the region –75/+151 and another in –2148/-1917, upstream of IGnTA gene. There is a potential GATA-1 binding site (TGATAG) in the region –75/+151 and a potential NF-E2/AP-1 binding site (CTGAGTCA) in the region –2148/-1917. In addition, the positive regulatory element located in the region –2148/-1917 might be an enhancer.