Table 1.
A summarized table showing validated and proposed candidate factors involved in histone-to-protamine transition: spg, spermatogonia; spc, spermatocytes; rspd, round spermatids; espd, elongating/elongated spermatids, NA, not applicable.
| Name | Expression | Localization | KO phenotype | References | |
|---|---|---|---|---|---|
| Histone variants | H1t | spc, rspd | nucleus | No detectable phenotype (mouse) |
(Lin et al. 2000) |
| H1T2 | rspd, espd | nucleus | Reduced fertility, morphological anomalies of sperm, defective DNA condensation (mouse) |
(Martianov et al. 2005, Tanaka et al. 2005) |
|
| TH2A | spg, spc, rspd, espd |
nucleus | Double KO of TH2A/TH2B led to infertility, degenerated spermatids, defects in TP1 and PRM2 transportation to nucleus (mouse) |
(Trostle-Weige et al. 1982, Shinagawa et al. 2015) |
|
| TH2B | spc, rspd, espd |
nucleus | TH2B KO mice are normal with compensatory enhancement of PTMs. C-terminal tagged TH2B Tg males were sterile. (mouse) |
(Montellier et al. 2013, Shinagawa et al. 2015) |
|
| H2AL1/2 | espd | Pericentric regions |
? | (Govin et al. 2007) | |
| H3.3 | Spg, spc, rspd, espd |
nucleus | Testicular atrophy; reduced and abnormal sperm; male infertility; reduced protamine incorporation; (mouse) |
(Bush et al. 2013, Yuen et al. 2014) |
|
| H3t | spc, rspd, espd |
nucleus | ? | (Tachiwana et al. 2008, Tachiwana et al. 2010) |
|
|
Histone modifications |
H3K9me1/2 | spc, rspd, espd |
nucleus | NA | (Liu et al. 2010) |
| H3K79me3 | espd (Step 9~11) |
nucleus | NA | (Dottermusch-Heidel et al. 2014a, Dottermusch-Heidel et al. 2014b) |
|
| H3K9ac | Espd | nucleus | NA | (Nair et al. 2008, Steilmann et al. 2011) |
|
| H4K5/K8/K12ac | espd (Step 9~) |
nucleus | NA | (Oliva & Mezquita 1982, Awe & Renkawitz-Pohl 2010) |
|
| RNF8 | spc, spd | nucleus | Normal MSCI, subfertile, defective nucleosome removal (mouse) |
(Lu et al. 2010, Ma et al. 2011) |
|
| SIRT1 | spg, spc (Step 1~9) |
nucleus | Decreased sperm output, reduced fertility, abnormal sperm head morphology, defects in H4K5/K8/K12ac (mouse) |
(Bell et al. 2014) | |
| Camk4 | espd | nucleus | Male sterility, Impaired spermatids, retention of TP2, loss of PRM2 (mouse) |
(Wu et al. 2000) | |
| PARP1/2 | espd | nucleus | Morphologically abnormal sperm; subfertility; retention of core histones (mouse) |
(Meyer-Ficca et al. 2005, Meyer-Ficca et al. 2009) |
|
|
Chromatin readers/remodelers |
PYGO2 | espd (Step 8~12) |
nucleus | Abnormal nuclear condensation; disrupted H3K9ac; infertility (mouse) |
(Nair et al. 2008, Gu et al. 2012) |
| ZMYND15 | rspd, espd | nucleus | Male infertility; sloughing of late spermatids (mouse) |
(Yan et al. 2010) | |
| CHD5 | rspd (Step 4~10) |
nucleus | reduced and abnormal sperm; male sub-fertility; failed histone-to- protamine transition (mouse) |
(Li et al. 2014a, Zhuang et al. 2014) |
|
| BRDT | Spc, rspd, espd (?) |
nucleus | Abnormal sperm morphology; infertility; retention of TH2B (mouse) |
(Shang et al. 2007, Berkovits & Wolgemuth 2011) |