The identification of the Prox gene family and the development of optical projection tomography for use in Zebrafish

Vertebrate homologues of the Drosophila melanogaster gene prospero have been identified in many species. Whilst the function and regulation of prospero has been well studied in Drosophila the function and regulation of the homologous vertebrate gene, praxl, is not known. We describe the identification of the prox genes as members of a multigene family in vertebrates through the isolation of new members of the Prox gene family in zebrafish, Fugu rubripes, Tetraodon nigroviridis, mouse, and human. We examined the phylogeny of this new multigene family and we characterised the expression of these novel genes in zebrafish. Analysis of the expression of these genes identified the slow muscle as site of expression for prox 1 that did not overlap with the novel zebrafish Prox genes. Therefore, we studied the function ofprox 1 in the slow muscle using a combination of DNA, and morpholino injections. We demonstrate that prox 1 in not required for the specification of slow muscle as determined by the expression of markers of terminal differentiation. We also show that the medial lateral migration of the slow muscle is unaffected by the loss of prox 1. However, ectopic expression of prox 1 specifically in the fast muscle causes a defect in nuclear patterning. In normal development the fast muscle cells fuse early to form a multinucleate syncytium. The nuclei in this syncytium are normally evenly spaced. Ectopic expression of prox 1 resulted in the nuclei of the fast cells being positioned at the centre of the syncytium similarly to the situation observed in the mononucleate slow muscle. Furthermore loss of Prox 1 results in the disrupted patterning of the slow fibres, demonstrating a role for Prox 1 in the patterning of the slow muscle fibres. An understanding of the 3-dimensional (3D) pattern of gene expression can often lead to a better understanding of gene function. Optical projection tomography (OPT) is a new method for obtaining 3D data about an object. OPT generates a 3D digital model of a sample and allows it to be virtually sectioned, or rendered to produce a 3D image. OPT was developed for use on mouse embryos and had not been tested with zebrafish. We describe the difficulties of using OPT on samples as small as zebrafish embryos and the development of techniques to overcome these problems and allow its use in zebrafish

Writing a book review

Book reviews are a good way to get started with writing for a journal and this Learning and CPD activity takes you through the process of understanding the aims of book review, undertaking practice pieces through to reviewing a book and advice on the dos and don'ts of book reviewing.N/

Correlation of currents with the distribution of adult daphnia in Lake Mendota

Simultaneous observations of current pattern and distribution of Daphnia pulex indicate that in Lake Mendota this zooplankter is concentrated by wind-induced convergence. Theoretical examination of this hypothesis yields results which compare favorably with observations

A Novel Thermal Gradient Design for Small-bodied Ectotherms

For ectothermic organisms, environmental temperatures can influence a variety of life history traits. Experimental thermal gradients created in the laboratory are useful tools to examine the thermoregulatory behaviors of these organisms. Here, we provide details on the construction of a novel, cost-effective thermal gradient to study thermoregulatory behaviors in small-bodied nocturnal ectotherms

Unimodal sequences and quantum and mock modular forms

We show that the rank generating function U(t; q) for strongly unimodal sequences lies at the interface of quantum modular forms and mock modular forms. We use U(-1; q) to obtain a quantum modular form which is “dual” to the quantum form Zagier constructed from Kontsevich’s “strange” function F(q). As a result, we obtain a new representation for a certain generating function for L-values. The series U(i; q) = U(-i; q) is a mock modular form, and we use this fact to obtain new congruences for certain enumerative functions