来自上海交通大学系统生物医学院的吴强教授近期在复杂基因簇研究方面又取得新的原创性成果，相关文章发表在PLoS One上。
尿苷二磷酸葡醛酸转移酶（UGT）基因簇和原钙粘蛋白基因簇具有相似的基因组结构，都具有可变区和恒定区，类似于生物抗体的基因结构，通过可变剪接可以产生非常多的蛋白质分子多样性。UGT蛋白家族在生物体化学防御和药物代谢系统中具有重要科学意义。例如，UGT蛋白家族在直肠癌药物伊利替康的肝脏代谢中起着举足轻重的作用。因此，研究UGT基因家族对研究药物在肝脏中的代谢机制，以及指导临床个性化药物治疗和合理用药、预测药物相互作用、减少药物不良反应、预防人类疾病都具有重要意义。但是，UGT分子多样性的产生机理还不清楚。
我们的大脑包含超过一千亿个神经元细胞，这些细胞形成约一百五十万亿个特异性的突触连接。阐明人类脑神经复杂连接的发育机理和大脑学习记忆的认知功能是生命科学的巨大挑战。原钙粘蛋白家族是大脑神经元细胞膜上具有细胞特异性表达模式的细胞粘连分子。原钙粘蛋白有非常复杂的分子多样性，可能在脑发育和脑功能方面起到重要作用。
该研究通过对基因打靶小鼠的表型分析，利用绿色荧光蛋白作为报告基因敲入原钙粘蛋白位点，发现一个原钙粘蛋白基因在大脑皮层发育过程中的中间神经元切线状和放射状迁移中起到重要作用。（生物谷Bioon.com）
生物谷推荐原始出处：
PLoS ONE 5(2): e9144. doi:10.1371/journal.pone.0009144
Cloning and Comparative Analyses of the Zebrafish Ugt Repertoire Reveal Its Evolutionary Diversity
Haiyan Huang1,2, Qiang Wu1,2*
1 Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, China, 2 State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University, Shanghai, China
UDP-glucuronosyltransferases (Ugts) are a supergene family of phase II drug-metabolizing enzymes that catalyze the conjugation of numerous hydrophobic small molecules with the UDP-glucuronic acid, converting them into hydrophilic molecules. Here, we report the identification and cloning of the complete zebrafish Ugt gene repertoire. We found that the zebrafish genome contains 45 Ugt genes that can be divided into three families: Ugt1, Ugt2, and Ugt5. Both Ugt1 and Ugt2 have two unlinked clusters: a and b. The Ugt1a, Ugt1b, Ugt2a, and Ugt2b clusters each contain variable and constant regions, similar to that of the protocadherin (Pcdh), immunoglobulin (Ig), and T-cell receptor (Tcr) clusters. Cloning the full-length coding sequences confirmed that each of the variable exons is separately spliced to the set of constant exons within each zebrafish Ugt cluster. Comparative analyses showed that both a and b clusters of the zebrafish Ugt1 and Ugt2 genes have orthologs in other teleosts, suggesting that they may be resulted from the “fish-specific” whole-genome duplication event. The Ugt5 genes are a novel family of Ugt genes that exist in teleosts and amphibians. Their entire open reading frames are encoded by single large exons. The zebrafish Ugt1, Ugt2, and Ugt5 genes can generate additional transcript diversity through alternative splicing. Based on phylogenetic analyses, we propose that the ancestral tetrapod and teleost Ugt1 clusters contained multiple Ugt1 paralogs. After speciation, these ancestral Ugt1 clusters underwent lineage-specific gene loss and duplication. The ancestral vertebrate Ugt2 cluster also underwent lineage-specific duplication. The intronless Ugt5 open reading frames may be derived from retrotransposition followed by gene duplication. They have been expanded dramatically in teleosts and have become the most abundant Ugt family in these lineages. These findings have interesting implications regarding the molecular evolution of genes with diversified variable exons in vertebrates.
