Molecular characterization of Xenopus lamin LIV reveals differences in the lamin composition of sperms in amphibians and mammals

Nuclear envelope remodelling during human spermiogenesis involves somatic B-type lamins and a spermatid-specific B3 lamin isoform

“…Nevertheless, there are four 5 ′ -ESTs from testis transcripts that begin within intron 4 (DB457056, HY047891, HY034239 and HY007444). Although such ESTs have been presented as evidence for a human lamin B3 (von Moeller et al, 2010), no experimental data has been presented describing their expression during human spermatogenesis. We reasoned that if these transcripts truly encode a human lamin B3 then they would, like their mouse counterpart, be expressed in spermatids.…”

“…Although four testis expressed sequence tags (ESTs) that encode a polypeptide lacking the lamin B2 N-terminus have been presented as evidence for the existence of a human lamin B3 (von Moeller et al, 2010), the predicted polypeptide shows no significant homology to the specific N-terminus of mouse lamin B3. Currently, there is no published experimental data to show whether these ESTs are derived from transcripts present in human spermatids, or whether the predicted lamin B2 isoform encoded by them has any effect on nuclear stability.…”

Dynamic properties of meiosis-specific lamin C2 and its impact on nuclear envelope integrity

“…58,59 Here, it was found that in contrast to the truncated mammalian lamins C2 and B3, Xenopus lamin LIV exhibits an extra sequence of 40 amino acids within the central α-helical rod that was predicted to impede coiled-coil formation. 58 Consistent with that, lamin LIV failed to assemble into bona fide filaments when expressed in Xenopus oocytes. Consequently, it was suggested that Xenopus lamin LIV and mammalian lamin B3 fulfill similar physiological functions.…”

“…57 Moreover, a recent study reported that human lamin B3 failed to assemble into bona fide lamin filaments when expressed in Xenopus oocytes. 58 Another male germ cell-specific lamin, lamin LIV, is present in the amphibian Xenopus laevis during post-meiotic stages of spermatogenesis and has recently been characterized on the molecular level in closer detail. 58,59 Here, it was found that in contrast to the truncated mammalian lamins C2 and B3, Xenopus lamin LIV exhibits an extra sequence of 40 amino acids within the central α-helical rod that was predicted to impede coiled-coil formation.…”

“…58 Another male germ cell-specific lamin, lamin LIV, is present in the amphibian Xenopus laevis during post-meiotic stages of spermatogenesis and has recently been characterized on the molecular level in closer detail. 58,59 Here, it was found that in contrast to the truncated mammalian lamins C2 and B3, Xenopus lamin LIV exhibits an extra sequence of 40 amino acids within the central α-helical rod that was predicted to impede coiled-coil formation. 58 Consistent with that, lamin LIV failed to assemble into bona fide filaments when expressed in Xenopus oocytes.…”