| Research Abstract |
We previously isolated the human LIMK2 gene and identified two alternative transcripts, LIMK2a and LIMK2b, which were differentially regulated in a tissue-specific manner. To investigate this mechanism and the transcription factors involved, we isolated the LIMK2a and 2b promoters. A luciferase reporter assay of the transcriptional activity revealed positive as well as negative regulatory regions within both promoters. The co-transfection assay suggested that the transcription factor, MZF-1, might regulate the expression of the LIMK2 isoforms in a different manner. The nuclear recptor, RORα1, might also be involved in the transcriptional regulation of the LIMK2b isoform. These findings should lead to a better understanding of the possibly diverse functions of the LIMK family.
We also isolated and studied the Ldb2 gene. The Ldb2 had the strong binding specificity to nuclar LIM proteins, which were thought to be involeved in the transcriptional regulation. The expression pattern of Ldb2 and its homologue Ldb1 were studied. The Ldb2 is expressed preferentially in normal lung, while the Ldb1 expression is increased in lung cancer tissues, suggesting the differential involvement of these genes in lung carcinogensis. We also examined the status of the Ldb2 gene in lung cancer cell lines. However, we could not find any genetic alteration.
|
