Isolation of a Promoter that Directs Microsporogenesis-Associated Gene Expression in Lilium longlfiorum.

Abstract

LIM genes, identified as cDNAs from pollen mother cells of Lillium longiflorum, are specifically induced at meiosis I of microsporogenesis. LIM8 encodes a protein which is highly homologous to amino acid transporters and exhibits high expression levels at late stages of microsporogenesis. To study the regulated expression of microsporogenesis-associated genes, we isolated a genomic clone containing the 5' upstream region of LIM8 gene by a PCR-based approach. Sequence analysis of the 0.6kb genomic DNA fragment revealed the presence of putative transcription factor binding sites. However, no sequence similarity was found in promoter regions of LIM8 gene and previously described meiosis-associated genes. Transient assay by microprojectile bombardment demonstrated that the putative promoter region of LIM8 gene is able to direct tissue-specific expression of the luciferase reporter gene in lily microsporocytes.