Role of Non-Muscle Myosin II in Regulating Cell Shape During Zebrafish Brain Morphogenesis

Mentor 1

Dr. Jennifer Gutzman

Location

Union Wisconsin Room

Start Date

28-4-2017 1:30 PM

End Date

28-4-2017 4:00 PM

Description

Cell shape changes during neural tube morphogenesis are essential for development of normal structure and function of the brain. In order to elucidate the molecular mechanisms that regulate cell shape changes in the developing brain, we examine the first fold in the neural tube that forms the highly conserved midbrain-hindbrain boundary (MHB). We use the zebrafish system for these studies because it allows for in vivo imaging at single cell resolution during early brain development. In zebrafish the MHB forms between 16 somite stage (ss) and primordium 6 (Prim-6), where a group of cells form the point of deepest constriction, the midbrain-hindbrain boundary constriction (MHBC). We previously determined that cells at the MHBC constrict basally and expand apically by Prim-6 to fold the tissue. We recently determined, using knockdown studies with antisense morpholino oligonucleotides, that non-muscle myosin II (NMII) protein isoforms, NMIIA (encoded by myh9) and NMIIB (encoded by myh10), differentially regulate cell shape changes during MHB morphogenesis. In order to further examine the roles for these proteins, we are using CRISPR-Cas9 genome editing to create myh9 and myh10 specific mutant zebrafish lines. This is essential to compare to our morpholino knockdown phenotypes. Our current results indicate that we have successfully generated F2 generation myh10 mutants and we are currently screening myh9 mutants. The examination of these mutant zebrafish lines will provide new insight into understanding the molecular mechanisms that mediate MHB formation, which are likely conserved in other morphogenetic events and in other vertebrate species.

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Apr 28th, 1:30 PM Apr 28th, 4:00 PM

Role of Non-Muscle Myosin II in Regulating Cell Shape During Zebrafish Brain Morphogenesis

Union Wisconsin Room

Cell shape changes during neural tube morphogenesis are essential for development of normal structure and function of the brain. In order to elucidate the molecular mechanisms that regulate cell shape changes in the developing brain, we examine the first fold in the neural tube that forms the highly conserved midbrain-hindbrain boundary (MHB). We use the zebrafish system for these studies because it allows for in vivo imaging at single cell resolution during early brain development. In zebrafish the MHB forms between 16 somite stage (ss) and primordium 6 (Prim-6), where a group of cells form the point of deepest constriction, the midbrain-hindbrain boundary constriction (MHBC). We previously determined that cells at the MHBC constrict basally and expand apically by Prim-6 to fold the tissue. We recently determined, using knockdown studies with antisense morpholino oligonucleotides, that non-muscle myosin II (NMII) protein isoforms, NMIIA (encoded by myh9) and NMIIB (encoded by myh10), differentially regulate cell shape changes during MHB morphogenesis. In order to further examine the roles for these proteins, we are using CRISPR-Cas9 genome editing to create myh9 and myh10 specific mutant zebrafish lines. This is essential to compare to our morpholino knockdown phenotypes. Our current results indicate that we have successfully generated F2 generation myh10 mutants and we are currently screening myh9 mutants. The examination of these mutant zebrafish lines will provide new insight into understanding the molecular mechanisms that mediate MHB formation, which are likely conserved in other morphogenetic events and in other vertebrate species.