Previously, we identified Speg (CG9723) as an inner nuclear membrane protein required for proper testis development. In speg mutants, flies have small testes that lack proper cyst structure and produce few late stage germ cells. To explore if speg functions in nuclear or chromatin organization, we examined speg null testes and enGal4-driven speg RNAi in wings with NLS-GFP. The nuclear envelope appears normal in speg mutants. Interestingly, heterochromatin protein 1 (HP1) is decreased in both speg mutant testes and wings. H3K4me3, H3K9me3, H3K27me3 and core histones are also decreased in speg mutant wings, suggesting a general requirement of speg for chromatin organization. We then performed DamID chromatin profiling in Kc cells. Bioinformatics analyses suggested that there are continuous Speg-associated domains spreading along Drosophila genome. The majority of Speg-associated domains are Black chromatin. Gene set enrichment analysis suggested that a subset of Speg-associated genes are significantly enriched in testis.