DCL5

{{Short description|Plant gene encoding a Dicer-like protein}}

{{Infobox nonhuman protein | Name = Endoribonuclease Dicer-like 5 (DCL5) | image = | width = | caption = | Organism = Zea mays | TaxID = 4577 | Symbol = DCL5 | AltSymbols = Zm00001eb045380 | PDB = | UniProt = | ECnumber = EC:3.1.26.3 }}

'''DICER-LIKE 5''' ('''DCL5''') is a plant Dicer-like endoribonuclease that functions in the biogenesis of 24-nucleotide reproductive phased small interfering RNAs (phasiRNAs). The gene is specific to monocots and plays a central role during early anther development, where these small RNAs accumulate at high levels.<ref name="Teng2020">{{cite journal |last1=Teng |first1=C. |last2=Zhang |first2=H. |last3=Hammond |first3=R. |last4=Huang |first4=K. |last5=Meyers |first5=B. C. |last6=Walbot |first6=V. |title=Dicer-like 5 deficiency confers temperature-sensitive male sterility in maize |journal=Nature Communications |volume=11 |issue=1 |page=2912 |year=2020 |doi=10.1038/s41467-020-16634-6 |pmid=32518237|pmc=7283321 |bibcode=2020NatCo..11.2912T }}</ref>

DCL5 originated through duplication and functional specialization of DCL3, giving rise to a distinct small RNA pathway associated with plant reproduction.<ref name="Margis">{{cite journal |last1=Margis |first1=R. |last2=Fusaro |first2=A. F. |last3=Smith |first3=N. A. |last4=Curtin |first4=S. J. |last5=Watson |first5=J. M. |last6=Finnegan |first6=E. J. |last7=Waterhouse |first7=P. M. |title=The evolution and diversification of Dicers in plants |journal=FEBS Letters |volume=580 |issue=10 |pages=2442–2450 |year=2006 |doi=10.1016/j.febslet.2006.03.072 |pmid=16638569 |bibcode=2006FEBSL.580.2442M }}</ref>

==Evolution==

Phylogenetic analyses indicate that DCL5 arose early in monocot evolution, likely before the diversification of grasses, and is absent from most eudicots.<ref name="Patel2021">{{cite journal |last1=Patel |first1=P. |last2=Mathioni |first2=S. M. |last3=Hammond |first3=R. |last4=Harkess |first4=A. E. |last5=Kakrana |first5=A. |last6=Arikit |first6=S. |last7=Dusia |first7=A. |last8=Meyers |first8=B. C. |title=Reproductive phasiRNA loci and DICER-LIKE5, but not microRNA loci, diversified in monocotyledonous plants |journal=Plant Physiology |volume=185 |issue=4 |pages=1764–1782 |year=2021 |doi=10.1093/plphys/kiab001 |pmid=33793935 |pmc=8133688}}</ref> Comparative genomics further places the origin of DCL5 at or before early-diverging monocots such as ''Acorus americanus'', suggesting an ancient duplication event followed by lineage-specific retention.<ref name="Belanger2023">{{cite journal |last1=Bélanger |first1=S. |last2=Zhan |first2=J. |last3=Meyers |first3=B. C. |title=Phylogenetic analyses of seven protein families refine the evolution of small RNA pathways in green plants |journal=Plant Physiology |volume=192 |issue=2 |pages=1183–1203 |year=2023 |doi=10.1093/plphys/kiad141 |pmid=36869858 |pmc=10231463}}</ref>

This duplication led to functional divergence between DCL3 and DCL5, with DCL3 primarily associated with heterochromatic siRNA pathways and DCL5 specialized for reproductive phasiRNA production in monocots.<ref name="Chen2022">{{cite journal |last1=Chen |first1=S. |last2=Liu |first2=W. |last3=Naganuma |first3=M. |last4=Tomari |first4=Y. |last5=Iwakawa |first5=H.-o. |title=Functional specialization of monocot DCL3 and DCL5 proteins through the evolution of the PAZ domain |journal=Nucleic Acids Research |volume=50 |issue=8 |pages=4669–4684 |year=2022 |doi=10.1093/nar/gkac223 |pmid=35380679|pmc=9071481 }}</ref>

The diversification of DCL5 parallels the expansion and diversification of reproductive phasiRNA loci in monocots, indicating co-evolution of this enzyme with its small RNA substrates.<ref name="Patel2021"/>

==Function==

DCL5 processes precursor transcripts into 24-nucleotide reproductive phasiRNAs that accumulate during premeiotic and meiotic stages of anther development.<ref name="Zhai2015">{{cite journal |last1=Zhai |first1=J. |last2=Zhang |first2=H. |last3=Arikit |first3=S. |last4=Huang |first4=K. |last5=Nan |first5=G. |last6=Walbot |first6=V. |last7=Meyers |first7=B. C. |title=Spatiotemporally dynamic, cell-type–dependent premeiotic and meiotic phasiRNAs in maize anthers |journal=Proceedings of the National Academy of Sciences USA |volume=112 |issue=10 |pages=3146–3151 |year=2015 |doi=10.1073/pnas.1418918112 |doi-access=free | pmid=25713378 |pmc=4364226 |bibcode=2015PNAS..112.3146Z }}</ref> DCL5 specifically mediates the biogenesis of reproductive phasiRNAs, a subclass of phased small interfering RNAs enriched in premeiotic and meiotic anthers.<ref name="Zhai2015"/>

These small RNAs are derived from ''PHAS'' precursor transcripts that are converted into double-stranded RNA and then processed into phased small interfering RNAs by DCL5.<ref name="Teng2020"/> In some nongrass monocots, many 24-nt reproductive phasiRNA precursors are predicted to form foldback or intramolecular duplex structures, indicating that DCL5-associated 24-nt reproductive phasiRNA biogenesis can proceed through more than one precursor structure or biogenesis pathway.<ref name="Kakrana2018">{{cite journal |last1=Kakrana |first1=A. |last2=Mathioni |first2=S. M. |last3=Huang |first3=K. |last4=Hammond |first4=R. |last5=Vandivier |first5=L. |last6=Patel |first6=P. |last7=Arikit |first7=S. |last8=Shevchenko |first8=O. |last9=Harkess |first9=A. E. |last10=Kingham |first10=B. |last11=Gregory |first11=B. D. |last12=Leebens-Mack |first12=J. H. |last13=Meyers |first13=B. C. |title=Plant 24-nt reproductive phasiRNAs from intramolecular duplex mRNAs in diverse monocots |journal=Genome Research |volume=28 |issue=9 |pages=1333–1344 |year=2018 |doi=10.1101/gr.228163.117 |pmid=30002159 |pmc=6120631}}</ref> In the canonical pathway, meiotic 24-nt reproductive phasiRNAs are triggered by the microRNA miR2275, which directs phased processing of precursor transcripts.<ref name="Song2012"/>

Genetic and molecular studies in rice initially identified this monocot-specific Dicer protein (DCL3b, later renamed DCL5) responsible for 24-nt phasiRNA production, distinct from DCL4, which generates 21-nt phasiRNAs.<ref name="Song2012">{{cite journal |last1=Song |first1=X. |last2=Li |first2=P. |last3=Zhai |first3=J. |last4=Zhou |first4=M. |last5=Ma |first5=L. |last6=Liu |first6=B. |last7=Jeong |first7=D.-H. |last8=Nakano |first8=M. |last9=Cao |first9=S. |last10=Liu |first10=C. |last11=Chu |first11=C. |last12=Wang |first12=X.-J. |last13=Green |first13=P. J. |last14=Meyers |first14=B. C. |last15=Cao |first15=X. |title=Roles of DCL4 and DCL3b in rice phased small RNA biogenesis |journal=The Plant Journal |volume=69 |issue=3 |pages=462–474 |year=2012 |doi=10.1111/j.1365-313X.2011.04805.x |pmid=21973320}}</ref>

Unlike DCL3, which processes RNA polymerase IV-derived transcripts, DCL5 acts primarily on transcripts generated by RNA polymerase II, reflecting mechanistic divergence between these pathways.<ref name="Chen2022" />

==Role in plant reproduction==

DCL5 is essential for normal male reproductive development in grasses. Loss-of-function mutations in ''DCL5'' lead to depletion of 24-nt reproductive phasiRNAs and defects in pollen development.<ref name="Teng2020"/> In maize and wheat, ''dcl5'' mutants exhibit temperature-sensitive male sterility, indicating that the DCL5 pathway contributes to fertility under specific environmental conditions.<ref name="Teng2020"/><ref name="Belanger2025">{{cite journal |last1=Bélanger |first1=S. |last2=Martín |first2=A. C. |last3=Marchant |first3=D. B. |last4=Zhan |first4=J. |last5=McGregor |first5=M. |last6=Smedley |first6=M. |last7=Hayta |first7=S. |last8=Moore |first8=G. |last9=Meyers |first9=B. C. |title=DICER-LIKE 5 loss causes thermosensitive male sterility in durum wheat and reveals an AU-rich motif guiding 24-nt phasiRNA biogenesis |journal=Proceedings of the National Academy of Sciences USA |volume=122 |issue=31 |article-number=e2504349122 |year=2025 |doi=10.1073/pnas.2504349122 |pmid=40737328 |pmc=12337324 |bibcode=2025PNAS..12204349B }}</ref>

Recent work suggests that some 24-nt reproductive phasiRNA biogenesis can occur independently of microRNA-directed cleavage and instead may involve conserved sequence motifs that guide DCL5-associated processing.<ref name="Belanger2025"/>

These findings support a model in which DCL5-dependent phasiRNAs contribute to transcriptional regulation and developmental robustness during male gametophyte formation.

==See also==

* Dicer * DCL1 * DCL2 * DCL3 * DCL4

==References== {{Reflist}} {{DEFAULTSORT:Dicer-like 5}}

Category:Plant genes Category:Ribonucleases Category:Proteins Category:RNA Category:RNA interference Category:RNA-binding proteins