Fertility and gamete reserves are maintained by asymmetric divisions of the germline stem cells to produce new stem cells or daughters that differentiate as gametes. Before entering meiosis, differentiating germ cells (GCs) of sexual animals typically undergo cystogenesis. This evolutionary conserved process involves synchronous and incomplete mitotic divisions of a GC daughter (cystoblast) to generate sister cells connected by intercellular bridges that facilitate exchange of materials to support rapid expansion of the gamete progenitor population. Here, we investigated cystogenesis in zebrafish and found that early GCs are connected by ring canals, and show that Deleted in azoospermia (Dazl), a conserved vertebrate RNA-binding protein (Rbp), as a regulator of this process. Analysis of dazl mutants revealed Dazl's essential role in regulating incomplete cytokinesis, germline cyst formation, and germline stem cell specification before the meiotic transition. Accordingly, dazl mutant GCs form defective ring canals, and ultimately remain as individual cells that fail to differentiate as meiocytes. In addition to promoting cystoblast divisions and meiotic entry, dazl is required for germline stem cell establishment and fertility.

Background. Surgery is sometimes required for the management of tubal ectopic pregnancies. Historically, surgeons used electrosurgery to obtain hemostasis. Topical hemostatic sealants, such as FloSeal, may decrease the reliance on electrosurgery and reduce thermal injury to the tissue. Case. A 33-year-old G1 P0 received methotrexate for a right tubal pregnancy. The patient became symptomatic six days later and underwent a laparoscopic right salpingotomy. After multiple unsuccessful attempts to obtain hemostasis with electrocoagulation, FloSeal was used and hemostasis was obtained. Six weeks later, a hysterosalpingogram (HSG) confirmed tubal patency. The patient subsequently had an intrauterine pregnancy. Conclusion. FloSeal helped to achieve hemostasis during a laparoscopic salpingotomy and preserve tubal patency. FloSeal is an effective alternative and adjunct to electrosurgery in the surgical management of tubal pregnancy.

Acquisition of oocyte polarity involves complex translocation and aggregation of intracellular organelles, RNAs, and proteins, along with strict posttranscriptional regulation. While much is still unknown regarding the formation of the animal-vegetal axis, an early marker of polarity, animal models have contributed to our understanding of these early processes controlling normal oogenesis and embryo development. In recent years, it has become clear that proteins with self-assembling properties are involved in assembling discrete subcellular compartments or domains underlying subcellular asymmetries in the early mitotic and meiotic cells of the female germline. These include asymmetries in duplication of the centrioles and formation of centrosomes and assembly of the organelle and RNA-rich Balbiani body, which plays a critical role in oocyte polarity. Notably, at specific stages of germline development, these transient structures in oocytes are temporally coincident and align with asymmetries in the position and arrangement of nuclear components, such as the nuclear pore and the chromosomal bouquet and the centrioles and cytoskeleton in the cytoplasm. Formation of these critical, transient structures and arrangements involves microtubule pathways, intrinsically disordered proteins (proteins with domains that tend to be fluid or lack a rigid ordered three-dimensional structure ranging from random coils, globular domains, to completely unstructured proteins), and translational repressors and activators. This review aims to examine recent literature and key players in oocyte polarity.

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