Research group Group Ozata
As a new research group aiming to construct an international work environment with a mutual respect, our main objective is to enthusiastically investigate how a mammalian male germ cell commits to become a functional sperm. Our studies will therefore advance our understanding of sperm development and may suggest approaches to promote fertility.
Group description
Male infertility has increased over the last two decades seven percent of which retains unknown reasons, thereby causing negative social and psychological impact. Sperm development (spermatogenesis) comprises an intricate and exquisitely programmed process of stem cell self-renewal, meiosis, and final differentiation that generates haploid, mature swimming sperm. Particularly, meiosis involves extensive changes in gene expression program that is critical for constructing mature swimming sperm. Therefore, precise regulation of gene expression program ensures male fertility.
We recently uncovered the novel function of a testis-specific transcription factor, TCFL5, during sperm development. In fact, transcription factors A-MYB and TCFL5 establish a central regulatory circuit that ensures the stepwise progression of spermatogenesis. However, two-fifths of genes required for sperm development are not regulated by this circuit, and thus we are interested in examining functions of additional transcription factors regulating sperm development.
Importantly, A-MYB–TCFL5 axis regulates ~100 specialized genes that produce highly abundant small RNAs, pachytene PIWI-interacting RNAs (piRNAs) that guide PIWI proteins to cleave/silence target transcripts. Only two of the mouse pachytene piRNA genes have mutant phenotypes: mice lacking pi6 or pi18 genes—on chromosomes 6 and 8—produce defective sperm. More puzzling, the sequences of pachytene piRNA genes unprecedentedly diverge faster than nearly all other genomic sequences in mammals, even among human individuals. Hence, the biological function of pachytene piRNAs is not well understood. We are therefore interested in exploring the evolutionary function of pachytene piRNAs during mammalian sperm development.
Group members
Group managers
Deniz Ozata
Researcher
Members
Mukhtar Mohammed
Student
Safiya Magan Gele
Student
Atiyeh Eghbali
PhD student
Martin Säflund
PhD student
Masomeh Askari
Postdokotor
Nart Jan A N Yaltchen
Student
