## Experiment Description Early human development requires precise regulation of gene expression in order to facilitate normal embryonic growth. Long noncoding RNAs (lncRNAs) are RNA transcripts lacking coding potential that regulate gene expression during development. We have identified a novel human-specific X-linked lncRNA called lncRHOXF2B, located in the RHOX cluster of the X chromosome. LncRHOXF2B is expressed from a 4.8kb gene to produce a 780 bp transcript, found in both the cytoplasm and the nucleus, and is subject to X-chromosome inactivation. To analyze the function of this novel lncRNA we targeted an inducible lncRHOXF2B transgene to chromosome 9 in human embryonic stem cells (hESCs).Overexpession of lncRHOXF2B in undifferentiated hESCs reduced cellular growth rates and increased differentiation. In this experiment, we examined the transcriptional profile of undifferentiated hESCs overexpressing lncRHOXF2B by illumina microarray. The expression profiling anaylsis along with highlighted results are reviewed below.