NIAMS logoBiotechnology is advancing at a faster rate helping experts analyze inside of a cells nucleus to further reveal secrets of its genetic material. Until now the happenings outside the nucleus were not known. The researchers from the National Institutes of Health took a step further in evaluating how a cell’s behavior depends on the outside of the nucleus.

The researchers observed mouse immune cells and the various types, amount and the activity of microRNAs, genetic components that stimulate production of proteins. This research provides a path to variety of microRNA contained within mouse immune cells. It further highlights the complexity of cellular protein regulation.

Cells containing genetic material are used to form an organism which is in the form of deoxyribonucleic acid (DNA) within the nucleus. Entire collection of an organism’s DNA is known as genome. It mainly consists of genes, short segments of DNA that code for proteins, and many long segments of DNA that do not contain genes. Each cell contains the entire genome. Protein is not made by all the cell genes all the time. Behavior of a cell is determined genes which are turned on and off. These behaviors include the type of cell it becomes, where it goes, and what it does.

“A plethora of cellular functions, ranging from development, differentiation, metabolism, and host defense, are impacted by protein levels,” said Rafael Casellas, Ph.D., the study’s principal investigator from the Genomics and Immunity Group of the NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). “We were interested in discovering how microRNAs contribute to the regulation of these functions.”

Transcription is a process through which a cell makes proteins. The genes are copied from DNA into messenger ribonucleic acid (RNA) which travels from the nucleus into the body of the cell. All RNA transferred from DNA is not messenger RNA. There are many other forms of RNA that do not code for proteins like small strands of RNA, MicroRNAs that adjust the production of proteins from messenger RNA. This help in regulating protein levels in the cell. Prior studies show that cells are very sensitive to fluctuations in miRNA levels which requires strict management for effective protein activity.

According to NIAMS Director Stephen I. Katz, M.D., Ph.D., “The data generated from this study represent a useful tool for immunologists and cell biologists to use for future studies on functional aspects of the immune system and basic miRNA biology.”

NIH scientists used the new micro sequencing technology in this research. This technology was used to identify all different miRNAs existing in the mouse immune cells. The researchers increased the number of known miRNAs and also identified several cellular mechanisms which helped to increase miRNA. The study also revealed that miRNA structures exist in dormant state within the nucleus until they receive signals from epigenome to become active. The epigenome regulates transcription and comprises all of the non-genetic material in the nucleus. Researchers identified that epigenetic mechanisms do not destroy other miRNAs. These miRNA are controlled through transcription. Greater amount of supply for some of these miRNAs depends upon the amount of target messenger RNA available in the cell.

This research appears online in the journal Immunity.