The mammalian sperm flagellum contains two cytoskeletal structures associated with the axoneme: the outer dense fibers surrounding the axoneme in the midpiece and principal piece and the fibrous sheath surrounding the outer dense fibers in the principal piece of the tail. Defects in these structures are associated with abnormal tail morphology, reduced sperm motility, and infertility. In the rat, the protein encoded by this gene associates with an outer dense fiber protein via a leucine zipper motif and localizes to the microtubules of the manchette and axoneme during sperm tail development. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Dec 2015]
Transcription factors with Perturb-seq knockdown data for SPAG4. The Binding column indicates whether any binding evidence exists for this TF–gene pair (ChIP-seq or motif footprint peaks). The Mean coef is the average Perturb-seq regression coefficient across active gRNAs (positive = SPAG4 upregulated upon KD; negative = downregulated). The Outlier column indicates whether this gene is in the top or bottom 5% of all TF knockdown effects.
| TF | Mean coef | Binding | Outlier | TF→Gene link |
|---|
Open chromatin peaks (ATAC-seq) in the genomic neighbourhood of SPAG4, linked by TSS proximity or chromatin conformation (Multiome / HiCAR). Each element overlaps at least one TF ChIP-seq binding site — the TFs column shows how many distinct TFs bind that element.
| Accessibility | Element | Dist. to TSS | Link type | TFs |
|---|---|---|---|---|
| chr20:35,454,521–35,455,845 | 161.9 kb | Distal (>10kb) Multiome | 1059 | |
| chr20:35,539,672–35,540,321 | 77.1 kb | Distal (>10kb) Multiome | 311 | |
| chr20:35,541,280–35,542,685 | 74.9 kb | Distal (>10kb) Multiome | 849 | |
| chr20:35,600,739–35,601,999 | 15.5 kb | Distal (>10kb) Multiome | 575 | |
| chr20:35,604,921–35,605,589 | 11.7 kb | Distal (>10kb) Multiome | 27 | |
| chr20:35,615,559–35,617,919 | 805 bp | At TSS Multiome | 1169 | |
| chr20:35,618,589–35,619,849 | 2.5 kb | Proximal (<10kb) Multiome | 865 | |
| chr20:35,664,428–35,665,171 | 47.9 kb | Distal (>10kb) Multiome | 1018 | |
| chr20:35,698,724–35,699,893 | 82.4 kb | Distal (>10kb) Multiome | 1035 | |
| chr20:35,741,564–35,742,903 | 125.4 kb | Distal (>10kb) Multiome | 1145 | |
| chr20:35,769,101–35,769,560 | 152.3 kb | Distal (>10kb) Multiome | 415 | |
| chr20:35,771,622–35,772,463 | 155.1 kb | Distal (>10kb) Multiome | 998 |
Genomic view of the SPAG4 locus showing ATAC-seq accessibility and RNA-seq expression across the ESC → DE time course, together with TF binding peaks and element-to-TSS loop connections.