Key regulator of male infertility

The protein complex known as Polycomb Repressive Complex 1 PRC1. PRC1 activates specific germline genes and the production of healthy sperm. It is responsible for production of health male sperm.

Male mammals are born with all the reproductive germline cells and inheritable genetics needed to make healthy fertile sperm and offspring. But the sperm isn't fertile at childhood.
PRC1 also blocks the specific genes and the activation of fertile sperm production until reproductive age.

Researchers show in their current study that when mice reach reproductive age, the PRC1 protein complex changes. It sheds reproductive germline gene components that block fertile sperm production and substitutes in a component that start spermatogenesis.

The repressor of sperm production, PRC1 also promotes gene activation to produce sperm at maturity. The scientists also found that when PRC1 is disrupted, such as in male mice bred to not express PRC1, the animals have smaller testes and are unable to produce healthy sperm or offspring.
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Human semen keeps viruses

The current analysis revealed genetic evidence of many infectious viruses found in semen. Semen provides a hiding place and breeding ground for many dangerous viruses

Zika, Ebola, Marburg, Lassa fever, Chikungunya, Mumps, Epstein-Barr and Chhicken pox are present in human semen. Non-sexually transmitted viruses can persist in semen, and this increases the risk of sexual transmission.

 The presence of viruses in semen does not mean that every virus can be sexually transmitted, common viruses in semen are: hepatitis viruses, herpes viruses, and range of other viruses that can be pass from person-to-person via blood, saliva or other means.

It is easy for viruses to get in to the semen, but relatively hard for the immune system to kill the viruses, the immune system recognized sperm as foreign objects in the body and this subject sperm to attack from the immune system.

For sperm to survive, the testes are immunologic locations in the body, where the immune system does not have much access to, this immunological location can also protect dangerous viruses.

Zika is cleared from the bloodstream within one week of treatment, but can persist in semen for months, Ebola survivors can reigniting an outbreak because the virus remained latent and active in their testicles.
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New method of correcting genetic infertility

Scientists have created healthy offspring from genetically infertile male mice, providing a new  method of correcting a genetic cause of human infertility.

Human sex is determined by the X and Y chromosomes. Usually, girls have two X chromosomes XX and boys have one X and one Y XY, but 1 in 500 boys are born with an extra X or Y.

Having three rather than two sex chromosomes can hinder formation of mature sperm and cause infertility.
Researchers have discovered a way to remove the extra sex chromosome to produce fertile offspring.

 If the findings can be safely transferred into humans, it might eventually be possible for men with Klinefelter syndrome XXY or double Y syndrome XYY that are infertile to have children through assisted reproduction using this method.

Researchers took small pieces of ear tissue from XXY and XYY mice, cultured them, and collected connective tissue cells known as fibroblasts. They turned the fibroblasts into stem cells and noticed that in the process, some of the cells lost the extra sex chromosome.

With an existing method, they used specific chemical signals to control the stem cells into becoming cells that have the potential to become sperm. These cells developed into mature sperm when injected into the testes of a host mouse.

 The researchers then harvested these mature sperm and used them through assisted reproduction to create healthy, fertile offspring.

Sperm cells have been created in the laboratory, offering hope for a cure for a common cause of male infertility.
About 1 in 500 men have an extra X or Y chromosome, which prevents their sperm production.
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