AUTHOR=Yellapragada Venkatram , Liu Xiaonan , Lund Carina , Känsäkoski Johanna , Pulli Kristiina , Vuoristo Sanna , Lundin Karolina , Tuuri Timo , Varjosalo Markku , Raivio Taneli 

TITLE=MKRN3 Interacts With Several Proteins Implicated in Puberty Timing but Does Not Influence GNRH1 Expression

JOURNAL=Frontiers in Endocrinology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2019.00048

DOI=10.3389/fendo.2019.00048

ISSN=1664-2392

ABSTRACT=<p>Paternally-inherited loss-of-function mutations in makorin ring finger protein 3 gene (<italic>MKRN3</italic>) underlie central precocious puberty. To investigate the puberty-related mechanism(s) of <italic>MKRN3</italic> in humans, we generated two distinct bi-allelic <italic>MKRN3</italic> knock-out human pluripotent stem cell lines, Del 1 and Del 2, and differentiated them into <italic>GNRH1</italic>-expressing neurons. Both Del 1 and Del 2 clones could be differentiated into neuronal progenitors and <italic>GNRH1</italic>-expressing neurons, however, the relative expression of <italic>GNRH1</italic> did not differ from wild type cells (<italic>P</italic> = NS). Subsequently, we investigated stable and dynamic protein-protein interaction (PPI) partners of MKRN3 by stably expressing it in HEK cells followed by mass spectrometry analyses. We found 81 high-confidence novel protein interaction partners, which are implicated in cellular processes such as insulin signaling, RNA metabolism and cell-cell adhesion. Of the identified interactors, 20 have been previously implicated in puberty timing. In conclusion, our stem cell model for generation of <italic>GNRH1</italic>-expressing neurons did not offer mechanistic insight for the role of MKRN3 in puberty initiation. The PPI data, however, indicate that MKRN3 may regulate puberty by interacting with other puberty-related proteins. Further studies are required to elucidate the possible mechanisms and outcomes of these interactions.</p>