Implications of Arabidopsis AKR protein in chloroplast development

The Arabidopsis AKR gene encodes a protein that contains four ankyrin repeats (AKR). Both sense and antisense AKR Arabidopsis tramsgenic plants demonstrated chlorosis in the true leaves. The first true leaf where chlorosis appeared is only partially chlorotic, green in the tip and white at the base. The chloroplast development is blocked in chlorotic leaf regions. In this study, I used electron microscopy to examine the structure of the plastids in the three regions of partially chlorotic leaves. Results of the chloroplast structural analysis showed that destruction of AKR function influences the formation of the thylakoid membrane system. In order to explore the relation-ship between the loss of AKR gene function and photosynthesis, I used immuno-gold labeling techniques to detect the rubisco protein in chlorotic leaf regions. Specific binding of both anti-rbcL and anti-RbcS antibodies in plastids of chlorotic leaf regions of mutant plants was lower than that in chloroplasts of wild-type plants. I have also used different tissues to localize the AKR protein. Furthermore, I used reverse transcription polymerase chain reaction (RT-PCR) to examine the transcription of the AKR gene in albino and chlorina mutant seedlings. A possible mechanism for the role of AKR protein in chloroplast development was briefly provided.