Developmental regulation of proteins during fruit-body morphogenesis in Sordaria brevicollis

Abstract

Specific morphogenetic events have been correlated with specific changes in polypeptide expression during ascomatal development in Sordaria brevicollis. Ascomatal morphogenesis was characterized using low-temperature SEM and light microscopy. Polypeptides were analysed by two-dimensional polyacrylamide gel electrophoresis. In vivo analyses involved isolating polypeptides from mycelia and fruit bodies and then examining them either unlabelled or after pulse-labelling with [35S]methionine. Polypeptides were also examined after in vitro translation of isolated mRNA. Of over 200 polypeptides detected after pulse-labelling, 31 were identified as being associated exclusively with sexual differentiation. Five of these polypeptides were specific to uncrossed protoperithecia; 9 were present in both protoperithecia and perithecia; and 17 were only detected in perithecia after crossing. Other changes in the level of polypeptide expression were also evident. The in vitro translation of mRNA showed some polypeptide expression during fruit-body morphogenesis to be under transcriptional control. None of the polypeptides detected have been identified but some were correlated with morphogenetic events which included (1) protoperithecium formation, (2) early perithecium development prior to neck emergence and ascus formation, (3) ascus and/or neck development, (4) ascospore formation, and (5) late stages of ascus or ascospore maturity. Cytochemical staining for laccase showed that this enzyme is subject to developmental regulation during fruit-body morphogenesis. Laccase activity was localized at sites of hyphal adhesion.