Student Research Projects

Expression analysis of centrins during spermatogenesis in the model moss Physcomitrella patens

Student Elizabeth Quamme, '17
Faculty Mentor(s)
Department Biology
Course Biology 489: Research in the Natural Sciences

Abstract

Physcomitrella patens, a member of one of the oldest lineages of plants, uses flagellated sperm cells to complete its life cycle. Its propensity for homologous recombination and its fully sequenced genome make this moss an ideal system for elucidating motile plant sperm cell biology. Centrins are Ca2+-binding proteins often associated with the basal bodies of eukaryotic organisms, including those linked with motile plant sperm cells. This research aimed to identify the expression profile of six putative centrins identified within the P. patens genome. We hypothesized that, as vital components of these cells, at least one centrin-encoding gene would show increased expression during spermatogenesis. To test this, RNA was extracted from gametangia-producing and vegetative tissues, converted to cDNA using reverse transcriptase, and expression levels were compared using semi-quantitative PCR. The results indicate that PpaCENTRIN4 (Pp1s160_86V6.1) was expressed in gametangia-producing tissue, but absent from vegetative tissue, suggesting that this gene evolved functional specificity to aid in sperm cell motility, converse to the other putative centrins tested. Supporting this, a BLAST analysis confirms that this gene, of the six identified, is most similar to a centrin characterized from the spermatogenous tissue of the aquatic fern, Marsilea vestida. Altogether, these data raise the possibility that centrins may be functionally specialized in plant cells. We are currently cloning PpaCENTRIN4 to further characterize its role in spermatogenesis, identify interacting proteins, and assess its expression in tissues not examined in the current study. These data will give a clearer understanding of the molecular interactions necessary for the development and function of the only flagellated cells in the plant kingdom.

Grants

Recipient of a research grant from the Virginia Foundation for Independent Colleges (VFIC), summer 2015.
Virginia Wesleyan Undergraduate Research Conference Grant, 2015-16.