Male mammalian meiosis and spermiogenesis is critically dependent on the shared functions of the katanins KATNA1 and KATNAL1

Abstract

Katanin microtubule severing enzymes are potent M-phase regulators in oocytes and somatic cells. How the complex, and evolutionarily critical, male mammalian meiotic spindle is sculpted remains unknown. Here, using multiple single and double gene knockout mice, we reveal that the canonical katanin A-subunit, KATNA1, and its close paralogue, KATNAL1, together execute multiple aspects of meiosis. We show KATNA1 and KATNAL1 collectively regulate the male meiotic spindle, cytokinesis and midbody abscission, in addition to diverse spermatid remodelling events, including Golgi organisation, and acrosome and manchette formation. We also define KATNAL1-specific roles in sperm flagella development, manchette regulation, and sperm-epithelial disengagement. Finally, using proteomic approaches we define the KATNA1, KATNAL1, and KATNB1 mammalian testis interactome, which includes a network of cytoskeletal and vesicle trafficking proteins. Collectively, we reveal the presence of multiple katanin A-subunit paralogs in mammalian spermatogenesis allows for ′customized cutting′ via neofunctionalization and protective buffering via gene redundancy.

Fertility is compromised after oocyte-specific deletion of Katanin A-subunit,Katna1, but notKatnal1

“…The increased sensitivity of the embryonic mitotic divisions to KATNA1 depletion compared to the meiotic divisions may be associated with the transition from an acentriolar spindle in oocytes to a more typical mitotic spindle with centrioles and focused spindle poles by the 8-32 cell stage (Courtois et al, 2012; Gueth-Hallonet et al, 1993; Palacios et al, 1993). This is also consistent with findings in spermatogenesis where centriolar spindles persist and, unlike oocytes, katanin deletion has a major impact on spindle organisation and function (Dunleavy et al, 2022; Dunleavy et al, 2021; O’Donnell et al, 2012). Thus, the increasingly important role of katanin in preimplantation embryos relative to the oocyte may be a manifestation of the transition from an acentriolar to centriolar spindle organisation.…”

“…Alternatively, there is increased evidence in a number of species that acute depletion of gene products leads to a more enhanced phenotype than genetic deletion in vivo , where compensatory mechanisms may come into play (El-Brolosy and Stainier, 2017; Tautz, 1992). In support of this, functional compensation of the katanin A-subunits has been documented (Dunleavy et al, 2022)…”

“…Loss of function studies have revealed katanins are critical regulators of microtubule organisation in a wide range of cellular processes, including mitosis, cilia biogenesis, neurogenesis and spermatogenesis (Banks et al, 2018; Dunleavy et al, 2022; Dunleavy et al, 2021; Dunleavy et al, 2017; Hu et al, 2014; Lombino et al, 2019; Lynn et al, 2021; McNally and Roll-Mecak, 2018; Mishra-Gorur et al, 2014; O’Donnell et al, 2012; Smith et al, 2012). The loss of katanin activity in regulating the length and dynamics of microtubules leads to errors in cell division, shape, and migration (Buster et al, 2002; Lombino et al, 2019; O’Donnell et al, 2012; Smith et al, 2012).…”

“…The loss of katanin activity in regulating the length and dynamics of microtubules leads to errors in cell division, shape, and migration (Buster et al, 2002; Lombino et al, 2019; O’Donnell et al, 2012; Smith et al, 2012). One of the best characterised roles for katanins is in male germ cell development, wherein Katna1, Katnal1, Katnal2 and Katnb1 are present in high levels, and knocking out these genes variously disrupts male meiosis, spermatid differentiation and Sertoli-germ cell adhesion (Dunleavy et al, 2022; Dunleavy et al, 2021; Dunleavy et al, 2017; O’Donnell et al, 2012; Smith et al, 2012).…”

Spastin is an essential regulator of male meiosis, acrosome formation, manchette structure and nuclear integrity

“…These include the bipolar spindle and midbody during mitosis and meiosis, the manchette for sperm head shaping, and the axoneme, which forms the architectural core of the sperm tail. Previous research has shown that spermatogenesis is dependent on microtubule severing through other members of the meiotic group of the AAA superfamily, the katanins KATNB1, KATNA1, KATNAL2 (summarised by Dunleavy et al, 2022 preprint). The role of spastin in the development of male germ cells has not yet been directly tested.…”