A modified cryosection method for mouse testis tissue

We have previously described a modified cryosection technique that improved the quality of histological sections as well as increasing the sensitivity to detect specific mRNA expression during early insect embryogenesis. Here, we report the use of this technique to produce high-quality sections of mouse testis tissue. The possibility of applying this technique to section the loose rat testis tissue is also discussed.

Double-segment defining role of even-skipped homologs along the evolution of insect pattern formation

Recent studies on insect patterning suggest that the genetic hierarchy may be roughly conserved in phylogenetically divergent species, but pair-rule genes may not function identically in all insects. In order to understand potential evolutionary changes in the role of the pair-rule genes, a Bombyx even-skipped homolog was cloned and its expression pattern during early embryogenesis studied. Eight stripes of Bombyx even-skipped were progressively expressed in an antero-posterior order. Later, these stripes disappeared anteriorly. Under this detection system, Bombyx even-skipped stripes clearly do not resolve into the corresponding secondary stripes, an obvious difference from Drosophila and Tribolium. These results suggest that Bombyx even-skipped may serve a double-segment defining role and may determine the odd-numbered engrailed stripes.