Characterization of two alternative splice variants associated with the Arabidopsis rhomboid protein gene At1g25290

Abstract

Rhomboid proteases are involved in various cellular activities, from development to cancer, and cellular processes and substrates associated with rhomboid proteases or rhomboid-like proteins have been identified for a range of organisms. Plant rhomboid proteases or rhomboid-like proteins are the least understood of the group. Moreover, the general phenomenon of alternative splicing and rhomboid protein genes has yet to be studied robustly. This study thus focused on the alternative splicing events associated with the Arabidopsis rhomboid protein gene At1g25290. The patterns obtained through RT-PCR and DNA sequencing provided evidence of alternative splicing in the At1g25290 transcript population, especially in the region spanning exons 5 and 6. The levels of the two splice variants involving exons 5 and 6 appear to be sufficiently abundant to possess functional significance and appear to adjust relative to each other in different contexts. Adjustments were observed in tissues of different developmental stages, in an Arabidopsis plant bearing a mutation in another rhomboid protein, and in response to transgenic manipulations affecting the levels of Tic40, a plastid translocon component. The resulting change to the protein sequence may, in turn, affect how At1g25290 proteins interact with their substrates. Collectively, the evidence suggests that alternative splicing of At1g25290 bears functional significance in Arabidopsis.