We recently attempted to measure mRNA expression in a series of rat cell lines using the primer for rat angiotensinogen mRNA (sense primer: 5-TCC CTG TCC TGT AAT CCC TC-3 and antisense primer: 5-GGC TGC TGC TCA TCA TTT AT-3) from the paper by Vidotti et al. (2) published in this journal, unfortunately without success.
After checking the primer with the rat angiotensinogen mRNA sequence database (NM 134432), we were surprised to find that the sense primer was not designed against mRNA. It did, however, match the intron of the rat angiotensinogen gene (L00094 [GenBank] ) reported as intron D in a previous study that analyzed the structural organization of the rat angiotensinogen gene (1).
Theoretically, this pair of primers should not be able to amplify the part of the rat angiotensiogen mRNA sequence. It is therefore puzzling that their data showed successful amplification by PCR reaction with a product size of 398 base pairs.
Given that Vidotti et al. (2) used this primer sequence in their study, we further question their finding that high glucose levels stimulate increased angiotensinogen expression in mesangial cells.
Moreover, if they were able to obtain the PCR products with this pair on a consistent basis, we suggest the possibility of genomic DNA contamination of the RNA samples and therefore also question the quality of the RNA purification used.
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