Two Human ACAT2 mRNA Variants Produced by Alternative Splicing and Coding for Novel Isoenzymes

Two Human ACAT2 mRNA Variants Produced by

Alternative Splicing and Coding for Novel

Isoenzymes

Xiao-Min YAO;Bo-Liang LI;Can-Hua WANG;Bao-Liang SONG;Xin-Ying YANG;Zhen-Zhen WANG;Wei QI;Zhi-Xin LIN;Catherine C. Y. CHANG;Ta-Yuan CHANG

【期刊名称】《生物化学与生物物理学报：英文版》 【年(卷),期】2005(037)012

【摘要】Acyl coenzyme A:cholesterol acyltransferase 2 (ACAT2) plays an important role in cholesterol absorption. Human ACAT2 is highly expressed in small intestine and fetal liver, but its expression is greatly diminished in adult liver. The full-length human ACAT2 mRNA encodes a protein, designated ACAT2a, with 522 amino acids. We have previously reported the organization of the human ACAT2 gene and the differentiation-dependent promoter activity in intestinal Caco-2 cells. In the current work, two human ACAT2 mRNA variants produced by alternative splicing are cloned and predicted to encode two novel ACAT2 isoforms,named ACAT2b and ACAT2c, with 502 and 379 amino acids, respectively. These mRNA variants differ from ACAT2a mRNA by lack of the exon 4 (ACAT2b mRNA) and exons 4-5 plus 8-9-10 (ACAT2c mRNA).Significantly, comparable amounts of the alternatively spliced ACAT2 mRNA variants were detected by RTPCR, and Western blot analysis confirmed the presence of their corresponding proteins in