Short communication: Translational efficiency of casein transcripts in Mediterranean river buffalo

Buffalo milk is characterized by the presence of all4 casein fractions (?S1, ?, ?S2, and ?) encoded by the4 tightly linked autosomal genes (CSN1S1, CSN2,CSN1S2, and CSN3, respectively). In the present paper,we report for the first time a quantitative characterizationof buffalo casein transcripts and show that the 4genes are not transcribed and translated with the sameefficiency. In particular, the analysis of individual milksamples obtained from 9 Mediterranean river buffaloesshowed that the most abundant casein fractions were? (53.45%) and ?S1 (20.61%), followed by ?S2 and ?, at14.28 and 11.66%, respectively. Quantification of thecorresponding mRNA showed that the percentage oftranscripts of the 4 caseins was 16.48, 23.18, 55.87, and4.47% for ?S1, ?, ?S2, and ?, respectively. Translation efficiencywas 0.25 for CSN1S2, 1.31 for CSN1S1, 2.39 forCSN2, and 2.69 for the CSN3 transcripts, respectively.A comparison of nucleotide sequences with the Kozakconsensus sequence was also carried out to investigateif the mRNA sequences might be responsible for theobserved differences.