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The embryonic origin of distinct fat depots and the role for ontogeny in specifying the functional differences among adipocyte lineages between and within depots is unclear. Using a Cre/Lox-based strategy to track the fate of major mesodermal subcompartments in mice we present evidence that <50% of interscapular brown adipocytes are derived from progenitors of the central dermomyotome. Furthermore, we demonstrate that depot-specific adipocyte lineages spatially diverge as early as gastrulation, and that perigonadal adipocytes arise from separate mesodermal subcompartments in males and females. Last, we show adipocyte precursors (APs) of distinct lineages within the same depot exhibit indistinguishable responses to a high fat diet, indicating that ontogenetic differences between APs do not necessarily correspond to functional differences in this context. Altogether, these findings shed light on adipose tissue patterning and suggest that the behavior of adipocyte lineage cells is not strictly determined by developmental history. [ABSTRACT FROM AUTHOR]

Transcription activator-like effector nucleases (TALENs) emerged as powerful tools for locus-specific genome engineering. Due to the ease of TALEN assembly, the key to streamlining TALEN-induced mutagenesis lies in identifying efficient TALEN pairs and optimizing TALEN mRNA injection concentrations to minimize the effort to screen for mutant offspring. Here we present a simple methodology to quantitatively assess bi-allelic TALEN cutting, as well as approaches that permit accurate measures of somatic and germline mutation rates inDrosophila melanogaster. We report that percent lethality from pilot injection of candidate TALEN mRNAs into Lig4 null embryos can be used to effectively gauge bi-allelic TALEN cutting efficiency and occurs in a dose-dependent manner. This timely Lig4-dependent embryonic survival assay also applies to CRISPR/Cas9-mediated targeting. Moreover, the somatic mutation rate of individual G0 flies can be rapidly quantitated using SURVEYOR nuclease and capillary electrophoresis, and germline transmission rate determined by scoring progeny of G0 outcrosses. Together, these optimized methods provide an effective step-wise guide for routine TALEN-mediated gene editing in the fly. [ABSTRACT FROM AUTHOR]