Diversity of smooth muscle within the vascular system is generated by alternative splicing of exons, yet there is limited understanding of its timing or control mechanisms. We examined splicing of myosin phosphatase regulatory subunit ( @entity63671 ) exon 24 (E24) in relation to @entity15108 ( @entity15108 ) and @entity68495 ( @entity68495 ) alternative exons ( @entity15108 E6 and @entity68495 E20) during maturation of @entity19 mesenteric artery (MA) smooth muscle. The role of transformer 2b ( @entity68496 ), a master regulator of splicing in flies, in maturation of arterial smooth muscle was tested through gene inactivation. Splicing of alternative exons in bladder smooth muscle was examined for comparative purposes. MA smooth muscle maturation began after postnatal week 2 and was complete at maturity, as indicated by switching to @entity63671 E24(+) and @entity68495 E20(-) splice variants and 11-fold induction of @entity15108 . Similar changes in bladder were complete by postnatal day 3. Splicing of @entity15108 E6 was temporally dissociated from @entity63671 E24 and @entity68495 E20 and discordant between arteries and bladder. @entity440 -induced smooth muscle-specific inactivation of @entity68496 within the first week of life but not in maturity reduced splicing of @entity63671 E24 in MAs. Inactivation of @entity68496 causing a switch to the isoform of @entity63671 containing the @entity1473 -terminal @entity368 zipper motif (E24(-)) increased arterial sensitivity to @entity6708 -mediated relaxation. In conclusion, maturation of @entity19 MA smooth muscle begins postnatally and continues until sexual maturity. @entity68496 is required for specification during this period of maturation, and its inactivation alters the contractile properties of mature arterial smooth muscle.

@entity68496 controls @entity63671 exon 24 splicing in the developmental maturation of XXXX mesenteric artery smooth muscle.

@entity6708 :: ('CHEBI:16356', 'Chemical') :: ['cGMP'] @entity440 :: ('MESH:D013629', 'Chemical') :: ['Tamoxifen'] @entity368 :: ('CHEBI:25017', 'Chemical') :: ['leucine'] @entity19 :: ('10090', 'Species') :: ['mouse'] @entity68495 :: ('29856(Tax:10090)', 'Gene') :: ['Smtn', 'smoothelin'] @entity15108 :: ('17880(Tax:10090)', 'Gene') :: ['smooth muscle myosin heavy chain', 'Smmhc'] @entity68496 :: ('20462(Tax:10090)', 'Gene') :: ['Tra2b', 'TRA2b'] @entity63671 :: ('17931(Tax:10090)', 'Gene') :: ['Mypt1', 'MYPT1'] @entity1473 :: ('CHEBI:46883', 'Chemical') :: ['COOH']
@entity19 :: (10090,Species) :: ['mouse']
