Histone H3K4 methylation is connected to gene transcription from yeast to humans, but its mechanistic role in transcription and chromatin dynamics remains poorly understood. Here, we investigated the functions for Set1 and Jhd2, the sole H3K4 methyltransferase and H3K4 demethylase, respectively, in S. cerevisiae. Our data show that Set1 and Jhd2 predominantly co-regulate transcription. We find combined activities of Set1 and Jhd2 via H3K4 methylation contribute to positive or negative transcriptional regulation at shared target genes. Providing mechanistic insights, our data reveal that Set1 and Jhd2 together control nucleosomal occupancy during transcriptional co-regulation. Moreover, we find a remarkable genome-wide co-regulation of nucleosome and chromatin structure by Set1 and Jhd2 at different groups of transcriptionally active or inactive genes and at different regions within yeast genes. Overall, our study prompts a model wherein combined actions of Set1 and Jhd2 via H3K4 methylation−demethylation control chromatin dynamics during various facets of transcriptional regulation. Genome-wide nucleosome maps were generated from three different yeast strains representing no tag control, 8V5-Set1 and Jhd2-12V5. Cells were cross-linked with formaldehyde, spheroplasted, nuclei were isolated and chromatin was prepared using micrococcal nuclease digestion , chromatin immunoprecipitation was performed using an epitope-tag specific antibody, libraries were prepared from ChIP and input DNA, sequenced, and analyzed separately.