Small RNAs have critical roles sperm formation

London, April 10 (ANI): Scientists at the University of Nevada School of Medicine claim that they have gained fresh insights into the reproductive workings of the male sex chromosome, which may have significant implications for male infertility and contraception.

The researchers have found that the X chromosome in developing sperm cells encodes numerous tiny ribonucleic acids called microRNAs despite the fact that that most of genes on the X chromosomes are suppressed.

According to them, this suggests that these small RNAs have critical roles in chromosome inactivation and also in sperm formation.

"The sex chromosome silencing in meiotic male germ cells is a well-known phenomenon, which has been termed meiotic sex chromosome inactivation. I was surprised when we first observed that numerous microRNAs were highly expressed in these cells," Nature magazine quoted lead researcher Dr. Wei Yan, an associate professor of Physiology and Cell Biology, as saying.

Yan joined forces with Dr. John McCarrey of University of Texas, San Antonio, to further investigate all the known X-linked microRNAs.

The researcher says that the research team's data confirm that these X chromosome-derived microRNAs indeed escape the silencing effects and mange to be expressed.

"This finding opens a new avenue towards understanding the role of these small RNA species in the control of sperm production. Worldwide, one in nine couples in their reproductive age experience infertility. On the other hand, the number of unintended pregnancy is increasing yearly. Since these small RNAs are involved in the control of sperm formation, they can be causative factors in male infertility and also can be used as non-hormonal male contraceptive targets," said Yan.

Funded by grants from the National Institutes of Health, Yan's research was focused on mammalian sperm and egg production.

A research article on the study has been published in the journal Nature Genetics. (ANI)