Brief Genetics Report Isolation and Characterization of the Human PAX4 Gene
Tsuyoshi Tao, Jon Wasson, Ernesto Bernal-Mizrachi, Philip S. Behn, Susan Chayen, Laura Duprat, Joanne Meyer, Benjamin Glaser, and M. Alan Permutt

AX genes are members of a family of developmental control genes that encode nuclear factors and play critical roles during fetal development (1). Results of recent gene targeting experiments revealed that Pax4 and Pax6 are involved in pancreatic islet development: Pax4 mutant mice lacked - and -cells (2), whereas Pax6 mutant mice lacked -cells (3). Because impaired insulin production by pancreatic islet -cells is a major hallmark of type 2 diabetes (4), genes that regulate pancreatic islet development and insulin biosynthesis might contribute to the pathogenesis of this disorder. As the first step to test the hypothesis that PAX4 might be one of these genes, we now report the isolation and characterization of the human PAX4 gene. The Basic Local Alignment Search Tool (BLAST) was used to search public databases with the partial sequence of the mouse Pax4 cDNA (GenBank accession no. Y09584). The search revealed highly homologous sequences in human cosmid clone g1572c264 (GenBank accession no. AC000359). We found that this human homolog appeared to be present in five separate fragments within a 2.5-kb region of this cosmid clone. Based on the sequence of this human homolog, we designed a pair of oligonucleotide primers (GSP1, 5 -TGGAATGCGGCCCTGTGACAT-3 ; GSP2, 5 -AGCTGCATTTCCCACTTGAGCT3 ). The partial cDNA of human PAX4 was amplified with these primers by polymerase chain reaction (PCR) with human placenta Marathon-Ready cDNA (Clontech, Palo Alto, CA) used as template. Thermal cycling was accomplished with Advantage cDNA Polymerase Mix (Clontech) at an annealing temperature of 60°C. Reaction products were subcloned and identified as the partial human PAX4 cDNA by sequencing. To isolate the 5 - and 3 -ends of the human PAX4 cDNA, 5 and 3 rapid