NORTHERN BLOT IDENTIFICATION OF MESSENGER-RNA CONTAINING SEQUENCE FORPROTEIN ALLERGEN, ALT A1, IN 8 STRAINS OF ALTERNARIA-ALTERNATA

Background: Concentrations of Alt a1, a major allergen from Alternaria alternata extracts, exhibit significant batch-to-batch variability. T his variability may result from basic strain-related genetic differenc es or from environmental influences such as growth conditions or extra ction methods. Objective: The objective of this work is to determine i f strain-to-strain allergen variability in Alternaria alternata, Alt a 1 allergen occurs at the nucleic acid level. Methods: We compared the content of mRNA for a segment known to contain sequence coding for the reported N-termini of this allergen in eight strains of Alternaria ob tained from three individual sources grown under identical conditions. RNA was extracted from rapidly growing mycelia and analyzed by northe rn blot analysis for the content of a specific segment containing sequ ence for the Alt a1 allergen. Blots were also analyzed for the content of a specific 5.8S rRNA segment. Results: The size of the mRNA for th is protein was about 700 bases. Sequence for the specific segment was found in all of the eight strains tested. When normalized for extracti on variabilities using the content of 5.8S rRNA, the calculated concen trations of Alt a1 mRNA of seven of the eight strains were similar. Co nclusions: The results of these experiments suggest that this Alt a1 r elated allergen sequence is found in many strains of Alternaria and th at variabilities in allergen protein content noted previously result f rom posttranslational events.