vasa is an RNA

RNA

Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 binding protein with an RNA dependant helicase

Helicase

Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...

. The vasa gene, is essential for germ cell

Germ cell

A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate near the gut of an embryo and migrate to the developing gonads. There, they undergo cell division of two types, mitosis and meiosis, followed by...

 development and was first identified in Drosophila melanogaster

Drosophila melanogaster

Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...

.

Expression

In Drosophila

Drosophila

Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...

, vasa expression is seen in germ cells, specifically the germline stem cells (GSC's) of female ovaries and in the early stages of spermatogensis in the male testis.

Staining

Due to the localization of vasa, immunohistochemistry

Immunohistochemistry

Immunohistochemistry or IHC refers to the process of detecting antigens in cells of a tissue section by exploiting the principle of antibodies binding specifically to antigens in biological tissues. IHC takes its name from the roots "immuno," in reference to antibodies used in the procedure, and...

 staining can be done with vasa antibodies. For example, vasa antibody staining is specific for germline stem cells in the D. melanogaster germarium.

Drosophila melanogaster

In early embryogenesis, vasa is involved in abdomen development, nanos mRNA translation, and pole plasm and germ cell formation. In oogenesis, vasa is involved in germline cyst development, oocyte differentiation, gurken mRNA translation, oocyte polarity and translation of oskar

Oskar

oskar is a gene required for the development of the Drosophila embryo. It defines the posterior pole during early embryogenesis....

mRNA.