LOW LEVEL LASER IRRADIATION ENHANCES EXPRESSION OF F0F1-ATPase SUBUNIT-b GENE IN OSTEOBLASTIC CELLS

Abstract

We previously constructed the cDNA library of osteoblastic cells using a stepwise subtraction procedure between cells with and without laser irradiation to identify any gene whose expression is enhanced by low level laser irradiation (LLLI). In the present study, we focused on a gene clone obtained from the subtracted cDNA library, designated as #201, which exhibited high homology with the gene coding for F0F1-ATPase subunit-b which is involved in the synthesis of ATP. To confirm the gene, the DNA sequence of the cDNA clone #201 was determined and assessed in DNA databases. The transcription level of the gene was examined by Northern blot analysis. Furthermore, the intracellular ATP content in laser irradiated cells was measured and compared with unirradiated cells. The DNA sequence of #201 clone exhibited 94.9% and 94.1% homology with rat and human F0F1-ATPase subunit-b gene, respectively. Higher F0F1-ATPase subunit-b mRNA levels were observed in laser irradiated cells compared with those in unirradiated cells. Furthermore, the content of ATP in laser irradiated cells was higher than that in unirradiated cells. These findings suggest that LLLI may play a principal role in accelerating ATP synthesis by stimulating the gene expression of F0F1-ATPase.